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Sample records for seal haul-out behavior

  1. Haul-out behavior of harbor seals (Phoca vitulina) in Hood Canal, Washington.

    PubMed

    London, Josh M; Ver Hoef, Jay M; Jeffries, Steven J; Lance, Monique M; Boveng, Peter L

    2012-01-01

    The goal of this study was to model haul-out behavior of harbor seals (Phoca vitulina) in the Hood Canal region of Washington State with respect to changes in physiological, environmental, and temporal covariates. Previous research has provided a solid understanding of seal haul-out behavior. Here, we expand on that work using a generalized linear mixed model (GLMM) with temporal autocorrelation and a large dataset. Our dataset included behavioral haul-out records from archival and VHF radio tag deployments on 25 individual seals representing 61,430 seal hours. A novel application for increased computational efficiency allowed us to examine this large dataset with a GLMM that appropriately accounts for temporal autocorellation. We found significant relationships with the covariates hour of day, day of year, minutes from high tide and year. Additionally, there was a significant effect of the interaction term hour of day : day of year. This interaction term demonstrated that seals are more likely to haul out during nighttime hours in August and September, but then switch to predominantly daylight haul-out patterns in October and November. We attribute this change in behavior to an effect of human disturbance levels. This study also examined a unique ecological event to determine the role of increased killer whale (Orcinus orca) predation on haul-out behavior. In 2003 and 2005 these harbor seals were exposed to unprecedented levels of killer whale predation and results show an overall increase in haul-out probability after exposure to killer whales. The outcome of this study will be integral to understanding any changes in population abundance as a result of increased killer whale predation. PMID:22723851

  2. Factors Affecting Haul-Out Behavior of Harbor Seals (Phoca vitulina) in Tidewater Glacier Inlets in Alaska: Can Tourism Vessels and Seals Coexist?

    PubMed Central

    2015-01-01

    Large numbers of harbor seals (Phoca vitulina) use habitat in tidewater glaciers in Alaska for pupping, breeding, and molting. Glacial fjords are also popular tourist destinations; however, visitation by numerous vessels can result in disturbance of seals during critical life-history phases. We explored factors affecting haul-out behavior of harbor seals at a glacial site frequented by tourism vessels. In 2008-10, we deployed VHF transmitters on 107 seals in Endicott Arm, Alaska. We remotely monitored presence and haul-out behavior of tagged seals and documented vessel presence with time-lapse cameras. We evaluated the influence of environmental and physical factors on the probability of being hauled out, duration of haul-out bouts, and as factors associated with the start and end of a haulout. Location, season, hour, and interactions of location by year, season, hour, and sex significantly influenced haul-out probability, as did ice, weather, and vessels. Seals were more likely to be hauled out with greater ice availability during the middle of the day, and less likely to be hauled out if vessels were present. Cruise ships had the strongest negative effect; however, most vessel types negatively affected haul-out probability. Haul-out duration was longest in association with starting on incoming tides, clear skies, no precipitation, occurring in the middle of the day, and ending in the late afternoon or evening. End of haulouts was associated with increasing cloud cover, low ice availability, and vessel presence; large-sized tourism vessels or all-vessel-types combined were significant predictors of ending a haul-out bout. Probability of being hauled out was highest in June, during pupping season. Potential disturbances of harbor seals could be reduced, enabling longer resting times for seals and fewer interruptions for nursing pups, if vessels focused the majority of visits to glacial habitat to before or after the hours of 08:00-17:00 or, less optimally, 09

  3. Modeling haul-out behavior of walruses in Bering Sea ice

    USGS Publications Warehouse

    Udevitz, M.S.; Jay, C.V.; Fischbach, A.S.; Garlich-Miller, J. L.

    2009-01-01

    Understanding haul-out behavior of ice-associated pinnipeds is essential for designing and interpreting popula-tion surveys and for assessing effects of potential changes in their ice environments. We used satellite-linked transmitters to obtain sequential information about location and haul-out state for Pacific walruses, Odobenus rosmarus divergens (Il-liger, 1815), in the Bering Sea during April of 2004, 2005, and 2006. We used these data in a generalized mixed model of haul-out bout durations and a hierarchical Bayesian model of haul-out probabilities to assess factors related to walrus haul-out behavior, and provide the first predictive model of walrus haul-out behavior in sea ice habitat. Average haul-out bout duration was 9 h, but durations of haul-out bouts tended to increase with durations of preceding in-water bouts. On aver-age, tagged walruses spent only about 17% of their time hauled out on sea ice. Probability of being hauled out decreased with wind speed, increased with temperature, and followed a diurnal cycle with the highest values in the evening. Our haul-out probability model can be used to estimate the proportion of the population that is unavailable for detection in spring surveys of Pacific walruses on sea ice.

  4. Bimodal Winter Haul-Out Patterns of Adult Weddell Seals (Leptonychotes weddellii) in the Southern Weddell Sea.

    PubMed

    Boehme, Lars; Baker, Amy; Fedak, Mike; Årthun, Marius; Nicholls, Keith; Robinson, Patrick; Costa, Dan; Biuw, Martin; Photopoulou, Theoni

    2016-01-01

    Hauling out is an essential component of pinniped life-history. Haul-out behaviour may be affected by biological (e.g. sex, age and condition) and physical factors (e.g. food availability and environmental conditions), and identifying these factors may help explain the spatio-temporal distribution and habitat use of pinnipeds. The aim of this study is to describe observed winter haul-out patterns of adult Weddell seals in the Weddell Sea and investigate the role of potential predictors to gain insight into the way these animals interact with the physical environment in this region. We examined the haul-out behaviour in relation to available biological (i.e., diving effort, sex) and physical information (i.e., sun angle). Thirty-three satellite telemetry tags were deployed on adult Weddell seals in the southern Weddell Sea during February 2007, 2009 and 2011, following their annual moult recording information on the behavioural mode of the animal: at surface, hauled out or diving. At the end of the austral summer Weddell seals spent, on average, more than 40% of their time hauled out on the ice. Under constant light conditions, it appears that physiological factors drive sex differences in the timing and duration of haul-out behaviour, with females spending on average more time hauled out than males during daylight hours. This time spent hauled-out declined to around 15% in both sexes by the beginning of autumn and remained at this level with a clear nocturnal haul-out pattern during the winter. The time spent diving increased during this period, indicating an increase in foraging effort during the winter months, and led to a common haul-out pattern in both sexes over winter. We found a positive relationship between haul-out duration and the percentage of time spent diving prior to a haul-out in both sexes, with the exception of female daytime haul-outs early in the year. PMID:27196097

  5. Bimodal Winter Haul-Out Patterns of Adult Weddell Seals (Leptonychotes weddellii) in the Southern Weddell Sea

    PubMed Central

    Fedak, Mike; Årthun, Marius; Nicholls, Keith; Robinson, Patrick; Costa, Dan; Biuw, Martin

    2016-01-01

    Hauling out is an essential component of pinniped life-history. Haul-out behaviour may be affected by biological (e.g. sex, age and condition) and physical factors (e.g. food availability and environmental conditions), and identifying these factors may help explain the spatio-temporal distribution and habitat use of pinnipeds. The aim of this study is to describe observed winter haul-out patterns of adult Weddell seals in the Weddell Sea and investigate the role of potential predictors to gain insight into the way these animals interact with the physical environment in this region. We examined the haul-out behaviour in relation to available biological (i.e., diving effort, sex) and physical information (i.e., sun angle). Thirty-three satellite telemetry tags were deployed on adult Weddell seals in the southern Weddell Sea during February 2007, 2009 and 2011, following their annual moult recording information on the behavioural mode of the animal: at surface, hauled out or diving. At the end of the austral summer Weddell seals spent, on average, more than 40% of their time hauled out on the ice. Under constant light conditions, it appears that physiological factors drive sex differences in the timing and duration of haul-out behaviour, with females spending on average more time hauled out than males during daylight hours. This time spent hauled-out declined to around 15% in both sexes by the beginning of autumn and remained at this level with a clear nocturnal haul-out pattern during the winter. The time spent diving increased during this period, indicating an increase in foraging effort during the winter months, and led to a common haul-out pattern in both sexes over winter. We found a positive relationship between haul-out duration and the percentage of time spent diving prior to a haul-out in both sexes, with the exception of female daytime haul-outs early in the year. PMID:27196097

  6. Thermal windows on the trunk of hauled-out seals: hot spots for thermoregulatory evaporation?

    PubMed

    Mauck, Björn; Bilgmann, Kerstin; Jones, Daryl D; Eysel, Ulf; Dehnhardt, Guido

    2003-05-01

    Seals have adapted to the high heat transfer coefficient in the aquatic environment by effective thermal insulation of the body core. While swimming and diving, excess metabolic heat is supposed to be dissipated mainly over the sparsely insulated body appendages, whereas the location of main heat sinks in hauled-out seals remains unclear. Here, we demonstrate thermal windows on the trunk of harbour seals, harp seals and a grey seal examined under various ambient temperatures using infrared thermography. Thermograms were analysed for location, size and development of thermal windows. Thermal windows were observed in all experimental sessions, shared some common characteristics in all seals and tended to reappear in similar body sites of individual seals. Nevertheless, the observed variations in order and location of appearance, number, size and shape of thermal windows would imply no special anatomical site for this avenue of heat loss. Based on our findings, we suggest that, in hauled-out seals, heat may be transported by blood flow to a small area of the wet body surface where the elevation of temperature facilitates evaporation of water trapped within the seals' pelages due to increased saturation vapour pressure. The comparatively large latent heat necessary for evaporation creates a temporary hot spot for heat dissipation. PMID:12682104

  7. Haul-Out Behaviour of the World's Northernmost Population of Harbour Seals (Phoca vitulina) throughout the Year

    PubMed Central

    Hamilton, Charmain D.; Lydersen, Christian; Ims, Rolf A.; Kovacs, Kit M.

    2014-01-01

    The harbour seal population in Svalbard occurs at the northernmost limit of the species' range. It experiences environmental extremes far beyond the norm for this species, including an extended period of polar night and extensive sea ice cover. In 2009 and 2010, 60 harbour seals (30 pups + 30 immature/mature seals) from this population were equipped with Satellite-Relay Data Loggers (SRDLs) to study their haul-out behaviour, with a special focus on the winter period. Using a combination of Generalized Additive Mixed Models and Cox Proportional Hazard models, the influences of sex, maturity, temporal, spatial and environmental factors on haul-out behaviour were explored. All of the seals continued to haul out even through the coldest periods during the polar night, though clear seasonality in the time spent hauled out daily was displayed by both immature and mature seals. Time spent hauled out daily decreased from ∼5.2 hrs in September to ∼1.2 hrs in February in these age groups, while pups displayed less seasonality (∼2.4 hrs/day throughout most of the year). The average at-sea period also exhibited seasonality, increasing to a maximum of ∼1.6 days in February (monthly maxima for individual animals ranged from 7 to 19 days). The seals showed a strong preference to haul out at low tide when hauling out on land but not when using sea ice as a haul-out platform. A diel rhythm in haul-out behaviour was present during the months with day–night cycling and midnight sun but not during the polar night. Haul-out behaviour was impacted to a greater extent by air pressure, through its effect on wind speed, than by absolute temperature values. The extreme environment in Svalbard likely causes some physiological challenges that might impact survival rates negatively, particularly among pups. Climate warming is likely to have positive effects on Svalbard's harbour seal population. PMID:24465867

  8. Fine-Scale Variability in Harbor Seal Foraging Behavior

    PubMed Central

    Wilson, Kenady; Lance, Monique; Jeffries, Steven; Acevedo-Gutiérrez, Alejandro

    2014-01-01

    Understanding the variability of foraging behavior within a population of predators is important for determining their role in the ecosystem and how they may respond to future ecosystem changes. However, such variability has seldom been studied in harbor seals on a fine spatial scale (<30 km). We used a combination of standard and Bayesian generalized linear mixed models to explore how environmental variables influenced the dive behavior of harbor seals. Time-depth recorders were deployed on harbor seals from two haul-out sites in the Salish Sea in 2007 (n = 18) and 2008 (n = 11). Three behavioral bout types were classified from six dive types within each bout; however, one of these bout types was related to haul-out activity and was excluded from analyses. Deep foraging bouts (Type I) were the predominant type used throughout the study; however, variation in the use of bout types was observed relative to haul-out site, season, sex, and light (day/night). The proportional use of Type I and Type II (shallow foraging/traveling) bouts differed dramatically between haul-out sites, seasons, sexes, and whether it was day or night; individual variability between seals also contributed to the observed differences. We hypothesize that this variation in dive behavior was related to habitat or prey specialization by seals from different haul-out sites, or individual variability between seals in the study area. The results highlight the potential influence of habitat and specialization on the foraging behavior of harbor seals, and may help explain the variability in diet that is observed between different haul-out site groups in this population. PMID:24717815

  9. Sleep and cardiac rhythm in the gray seal.

    PubMed

    Ridgway, S H; Harrison, R J; Joyce, P L

    1975-02-14

    Telemetric studies of electroencephalograms, electrocardiograms, and electroculograms and concurrent observations of behavior revealed that seals can sleep underwater, on the surface, or while hauled out. Rapid eye movement preceded slow wave sleep and was accompanied by increased respiratory rate and rhythmic tachycardia. While slow wave sleep occurred under all sleep conditions, rapid eye movement occurred only when a seal was hanging at the water surface or hauled out, never underwater. PMID:163484

  10. Behavioral effects of environmental enrichment on harbor seals (Phoca vitulina concolor) and gray seals (Hafichoerus grypus)

    USGS Publications Warehouse

    Hunter, S.A.; Bay, M.S.; Martin, M.L.; Hatfield, J.S.

    2002-01-01

    Zoos and aquariums have been incorporating environmental enrichment into their animal care programs for the past 30 years to increase mental stimulation and promote natural behaviors. However, most attempts to document the effects of enrichment on animal behavior have focused on terrestrial mammals. Staff at the National Aquarium in Baltimore conducted an investigation of the behavioral effects of enrichment on the seven harbor seals and two gray seals housed in the aquarium's outdoor seal exhibit. We expected that enrichment would change the amount of time the animals spent engaged in specific behaviors. The behaviors recorded were: resting in water, resting hauled out, maintenance, breeding display, breeding behavior, aggression, pattern swimming, random swimming, exploration, and out of sight. Activity levels (random swimming and exploration) were expected to increase, while stereotypic behaviors (pattern swimming) were expected to decrease. The frequency and duration of behaviors were documented for 90 hr in both the control phase (without enrichment) and the experimental phase (with enrichment). Statistically significant differences (P<0.05) in the time spent in pattern swimming, random swimming, exploration, and out of sight were observed between the two phases. With enrichment, pattern swimming and out of sight decreased, while random swimming and exploration behavior increased. These findings demonstrate that enrichment can promote behaviors (random swimming and exploration) that are likely to be normal for phocids in the wild, and that may contribute to the behavioral complexity of these seals in captivity.

  11. Behavioral effects of environmental enrichment on harbor seals (Phoca vitulina concolor) and gray seals (Halichoerus grypus)

    USGS Publications Warehouse

    Hunter, S.A.; Bay, M.S.; Martin, M.L.; Hatfield, J.S.

    2002-01-01

    Zoos and aquariums have been incorporating environmental enrichment into their animal care programs for the past 30 years to increase mental stimulation and promote natural behaviors. However, most attempts to document the effects of enrichment on animal behavior have focused on terrestrial mammals. Staff at the National Aquarium in Baltimore conducted an investigation of the behavioral effects of enrichment on the seven harbor seals and two gray seals housed in the aquarium's outdoor seal exhibit. We expected that enrichment would change the amount of time the animals spent engaged in specific behaviors. The behaviors recorded were: resting in water, resting hauled out, maintenance, breeding display, breeding behavior, aggression, pattern swimming, random swimming, exploration, and out of sight. Activity levels (random swimming and exploration) were expected to increase, while stereotypic behaviors (pattern swimming) were expected to decrease. The frequency and duration of behaviors were documented for 90 hr in both the control phase (without enrichment) and the experimental phase (with enrichment). Statistically significant differences (P < 0.05) in the time spent in pattern swimming, random swimming, exploration, and out of sight were observed between the two phases. With enrichment, pattern swimming and out of sight decreased, while random swimming and exploration behavior increased. These findings demonstrate that enrichment can promote behaviors (random swimming and exploration) that are likely to be normal for phocids in the wild, and that may contribute to the behavioral complexity of these seals in captivity. ?? 2002 Wiley-Liss, Inc.

  12. Response of Pacific walruses to disturbances from capture and handling activities at a haul-out in Bristol Bay, Alaska

    USGS Publications Warehouse

    Jay, C.V.; Olson, T.L.; Garner, G.W.; Ballachey, B.E.

    1998-01-01

    Observations were made on hems of the Pacific walrus (Odobenus rosmarus divergens) to study their response during the capturing and handling of adult males in summer 1995 at a haul-out at Cape Peirce in southwestern Alaska. Three behaviors (alertness, displacement, and dispersal) were quantified from 16 capture sessions. Herd sizes ranged from 622 to 5,289 walruses. Handling of an immobilized walrus consisted of attempts to attach telemetry devices to the tusks and collect various biological samples. Handling activities resulted in an average of about 10-fold or greater levels of behavior in alertness, displacement, and dispersal than during precapture and darting periods. High levels of behavior usually occurred within the first 45 min of handling. In 8 of 10 capture sessions, walruses returned to predisturbance levels of behavior within 40 min of cessation of the handling disturbance. Alertness and displacement were moderately and negatively correlated with herd size during the handling period, which may reflect an effect of a threshold distance from the point of disturbance to responding individuals. Observations of walruses tagged with VHF radio transmitters indicated that the activities from a given capture session did not preclude tagged walruses from using the haul-out over a subsequent 11-wk monitoring period. Moreover, non-tagged walruses continued to extensively use the haul-out during and after the period in which capture sessions were conducted.

  13. Winter habitat use and foraging behavior of crabeater seals along the Western Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Burns, Jennifer M.; Costa, Daniel P.; Fedak, Michael A.; Hindell, Mark A.; Bradshaw, Corey J. A.; Gales, Nicholas J.; McDonald, Birgitte; Trumble, Stephen J.; Crocker, Daniel E.

    2004-08-01

    We quantified the winter and spring movement patterns and foraging behavior of adult crabeater seals ( Lobodon carcinophagus), and the influence of sea ice and bathymetry on their foraging behavior. Thirty-four seals (16 M 18 F) were outfitted with Satellite Relay Data Loggers (SRDLs) in the Marguerite Bay Region of the Antarctic Peninsula (˜67°S, 67°W) during the austral winters of 2001 and 2002. Tags transmitted position and dive information for between 4 and 174 days. Overall, winter activity patterns differed significantly from previously reported data collected during the summer: seals in this study dived deeper (92±0.2 m, range 6-713 m) and longer (5.26 min±0.6, range 0.2-23.6 min), hauled out during the night rather than the day, and showed seasonal shifts in foraging patterns consistent with foraging on vertically migrating prey. While these patterns were more pronounced in 2001 than in 2002, there were no strong differences in patterns of habitat use between the 2 years. Some animals made long distance movements (furthest movements 664 km to northeast, 1147 km to southwest), but most seals remained within 300 km of their tagging location. Within the Marguerite Bay/Crystal Sound region, seals appeared to favor foraging locations on the continental shelf within the 50 to 450 m depth range, with a tendency to avoid depths of 600 m or greater. In both years, seals remained deep within the pack ice throughout the winter, and did not move into regions with less ice cover. Seals were more likely to be located in shallow water where the bathymetric gradients were greatest, and in areas of higher sea-ice concentration. In combination, these findings suggest that crabeater seals alter their behavior to accommodate seasonal and/or annual fluctuations in seasonal sea ice and associate with bathymetric features likely to concentrate prey patches.

  14. Observer variability in pinniped counts: Ground-based enumeration of walruses at haul-out sites

    USGS Publications Warehouse

    Udevitz, M.S.; Jay, C.V.; Cody, M.B.

    2005-01-01

    Pinnipeds are often monitored by counting individuals at haul-out sites, but the often large numbers of densely packed individuals at these sites are difficult to enumerate accurately. Errors in enumeration can induce bias and reduce precision in estimates of population size and trend. We used data from paired observers monitoring walrus haul-outs in Bristol Bay, Alaska, to quantify observer variability and assess its relative importance. The probability of a pair of observers making identical counts was 50 individuals. Mean count differences ranged up to 25% for the largest counts, depending on beach and observers. In at least some cases, there was a clear tendency for counts of one observer to be consistently greater than counts of the other observer in a pair, indicating that counts of at least one of the observers were biased. These results suggest that efforts to improve accuracy of counts will be worthwhile. However, we also found that variation among observers was relatively small compared to variation among visits to a beach so that efforts to account for other sources of variation will be more important.

  15. A magnetic fluid seal for rotary blood pumps: Behaviors of magnetic fluids in a magnetic fluid seal.

    PubMed

    Mitamura, Yoshinori; Yano, Tetsuya; Nakamura, Wataru; Okamoto, Eiji

    2013-01-01

    A magnetic fluid (MF) seal has excellent durability. The performance of an MF seal, however, has been reported to decrease in liquids (several days). We have developed an MF seal that has a shield mechanism. The seal was perfect for 275 days in water. To investigate the effect of a shield, behaviors of MFs in a seal in water were studied both experimentally and computationally. (a) Two kinds of MF seals, one with a shield and one without a shield, were installed in a centrifugal pump. Behaviors of MFs in the seals in water were observed with a video camera and high-speed microscope. In the seal without a shield, the surface of the water in the seal waved and the turbulent flow affected behaviors of the MFs. In contrast, MFs rotated stably in the seal with a shield in water even at high rotational speeds. (b) Computational fluid dynamics analysis revealed that a stationary secondary flow pattern in the seal and small velocity difference between magnetic fluid and water at the interface. These MF behaviors prolonged the life of an MF seal in water. PMID:23442238

  16. Underwater and surface behavior of homing juvenile northern elephant seals.

    PubMed

    Matsumura, Moe; Watanabe, Yuuki Y; Robinson, Patrick W; Miller, Patrick J O; Costa, Daniel P; Miyazaki, Nobuyuki

    2011-02-15

    Northern elephant seals, Mirounga angustirostris, travel between colonies along the west coast of North America and foraging areas in the North Pacific. They also have the ability to return to their home colony after being experimentally translocated. However, the mechanisms of this navigation are not known. Visual information could serve an important role in navigation, either primary or supplementary. We examined the role of visual cues in elephant seal navigation by translocating three seals and recording their heading direction continuously using GPS, and acceleration and geomagnetic data loggers while they returned to the colony. The seals first reached the coast and then proceeded to the colony by swimming along the coast. While underwater the animals exhibited a horizontally straight course (mean net-to-gross displacement ratio=0.94±0.02). In contrast, while at the surface they changed their headings up to 360 deg. These results are consistent with the use of visual cues for navigation to the colony. The seals may visually orient by using landmarks as they swim along the coast. We further assessed whether the seals could maintain a consistent heading while underwater during drift dives where one might expect that passive spiraling during drift dives could cause disorientation. However, seals were able to maintain the initial course heading even while underwater during drift dives where there was spiral motion (to within 20 deg). This behavior may imply the use of non-visual cues such as acoustic signals or magnetic fields for underwater orientation. PMID:21270312

  17. Experimental and analytical tools for evaluation of Stirling engine rod seal behavior

    NASA Technical Reports Server (NTRS)

    Krauter, A. I.; Cheng, H. S.

    1979-01-01

    The first year of a two year experimental and analytical program is reported. The program is directed at the elastohydrodynamic behavior of sliding elastomeric rod seals for the Stirling engine. During the year, experimental and analytical tools were developed for evaluating seal leakage, seal friction, and the fluid film thickness at the seal/cylinder interface.

  18. Resource partitioning through oceanic segregation of foraging juvenile southern elephant seals ( Mirounga leonina).

    PubMed

    Field, Iain C; Bradshaw, Corey J A; Burton, Harry R; Sumner, Michael D; Hindell, Mark A

    2005-01-01

    In highly dynamic and unpredictable environments such as the Southern Ocean, species that have evolved behaviors that reduce the effects of intra-specific competition may have a selective advantage. This is particularly true when juveniles face disadvantages when foraging due to morphological or physiological limitation, which is the case for many marine mammals. We tracked the at-sea movements of 48 juvenile southern elephant seals ( Mirounga leonina) between the ages of 1 and 4 years from the population at Macquarie Island using locations derived from recorded light levels. There were significant differences in the total amount of the Southern Ocean covered by the different age-groups. The younger seals used a smaller area than the older seals. On average, the younger individuals also made more trips to sea than the older seals and did not travel as far on each trip. Females spent more time at sea than males and there were no significant differences between the total areas used by male and females. In summary, younger seals remained closer to the island at all times, and they spent more time in more northerly regions that older seals. These differences in behavior created temporal and spatial segregation between juveniles of different ages. Therefore, we suggest that these temporal and spatial separations help to avoid intra-specific competition for resources on land, space on beaches, and at-sea foraging areas. Such modifications of haul-out timing and behavior enable them to exploit a patchy and unpredictable environment. PMID:15365810

  19. Abundance of ringed seals (Pusa hispida) in the fjords of Spitsbergen, Svalbard, during the peak molting period

    USGS Publications Warehouse

    Krafft, B.A.; Kovacs, K.M.; Andersen, M.; Aars, J.; Lydersen, C.; Ergon, T.; Haug, T.

    2006-01-01

    Ringed seal (Pusa hispida) abundance in Spitsbergen, Svalbard, was estimated during the peak molting period via aerial, digital photographic surveys. A total of 9,145 images, covering 41.7%?100% of the total fast-ice cover (1,496 km2) of 18 different fjords and bays, were inspected for the presence of ringed seals. A total of 1,708 seals were counted, and when accounting for ice areas that were not covered by images, a total of 3,254 (95% CI: 3,071?3,449) ringed seals were estimated to be hauled out during the surveys. Extensive behavioral data from radio-tagged ringed seals (collected in a companion study) from one of the highest density fjords during the molting period were used to create a model that predicts the proportion of seals hauled out on any given date, time of day, and under various meteorological conditions. Applying this model to the count data from each fjord, we estimated that a total of 7,585 (95% CI: 6,332-9,085) ringed seals were present in the surveyed area during the peak molting period. Data on interannual variability in ringed seal abundance suggested higher numbers of seals in Van Keulenfjorden in 2002 compared to 2003, while other fjords with very stable ice cover showed no statistical differences. Poor ice conditions in general in 2002 probably resulted in seals from a wide area coming to Van Keulenfjorden (a large fjord with stable ice in 2002). The total estimated number of ringed seals present in the study area at the time of the survey must be regarded as a population index, or at least a minimum estimate for the area, because it does not account for individuals leaving and arriving, which might account for a considerable number of animals. The same situation is likely the case for many other studies reporting aerial census data for ringed seals. To achieve accurate estimates of population sizes from aerial surveys, more extensive knowledge of ringed seal behavior will be required.

  20. Influence analysis of secondary O-ring seals in dynamic behavior of spiral groove gas face seals

    NASA Astrophysics Data System (ADS)

    Hu, Songtao; Huang, Weifeng; Liu, Xiangfeng; Wang, Yuming

    2016-05-01

    The current research on secondary O-ring seals used in mechanical seals has begun to focus on their dynamic properties. However, detailed analysis of the dynamic properties of O-ring seals in spiral groove gas face seals is lacking. In particular a transient study and a difference analysis of steady-state and transient performance are imperative. In this paper, a case study is performed to gauge the effect of secondary O-ring seals on the dynamic behavior (steady-state performance and transient performance) of face seals. A numerical finite element method (FEM) model is developed for the dynamic analysis of spiral groove gas face seals with a flexibly mounted stator in the axial and angular modes. The rotor tilt angle, static stator tilt angle and O-ring damping are selected to investigate the effect of O-ring seals on face seals during stable running operation. The results show that the angular factor can be ignored to save time in the simulation under small damping or undamped conditions. However, large O-ring damping has an enormous effect on the angular phase difference of mated rings, affecting the steady-state performance of face seals and largely increasing the possibility of face contact that reduces the service life of face seals. A pressure drop fluctuation is carried out to analyze the effect of O-ring seals on the transient performance of face seals. The results show that face seals could remain stable without support stiffness and O-ring damping during normal stable operation but may enter a large-leakage state when confronting instantaneous fluctuations. The oscillation-amplitude shortening effect of O-ring damping on the axial mode is much greater than that on the angular modes and O-ring damping prefers to cater for axial motion at the cost of angular motion. This research proposes a detailed dynamic-property study of O-ring seals in spiral groove gas face seals, to assist in the design of face seals.

  1. Influence analysis of secondary O-ring seals in dynamic behavior of spiral groove gas face seals

    NASA Astrophysics Data System (ADS)

    Hu, Songtao; Huang, Weifeng; Liu, Xiangfeng; Wang, Yuming

    2016-04-01

    The current research on secondary O-ring seals used in mechanical seals has begun to focus on their dynamic properties. However, detailed analysis of the dynamic properties of O-ring seals in spiral groove gas face seals is lacking. In particular a transient study and a difference analysis of steady-state and transient performance are imperative. In this paper, a case study is performed to gauge the effect of secondary O-ring seals on the dynamic behavior (steady-state performance and transient performance) of face seals. A numerical finite element method (FEM) model is developed for the dynamic analysis of spiral groove gas face seals with a flexibly mounted stator in the axial and angular modes. The rotor tilt angle, static stator tilt angle and O-ring damping are selected to investigate the effect of O-ring seals on face seals during stable running operation. The results show that the angular factor can be ignored to save time in the simulation under small damping or undamped conditions. However, large O-ring damping has an enormous effect on the angular phase difference of mated rings, affecting the steady-state performance of face seals and largely increasing the possibility of face contact that reduces the service life of face seals. A pressure drop fluctuation is carried out to analyze the effect of O-ring seals on the transient performance of face seals. The results show that face seals could remain stable without support stiffness and O-ring damping during normal stable operation but may enter a large-leakage state when confronting instantaneous fluctuations. The oscillation-amplitude shortening effect of O-ring damping on the axial mode is much greater than that on the angular modes and O-ring damping prefers to cater for axial motion at the cost of angular motion. This research proposes a detailed dynamic-property study of O-ring seals in spiral groove gas face seals, to assist in the design of face seals.

  2. Behavior of some sealing arrangements for machine tool spindles

    SciTech Connect

    Philpott, M.L.; Colton, M.W.; Cusano, C.

    1995-09-01

    A test stand has been built and instrumented to simulate conditions in the spindle cavity of production machine tools, such as high-speed transfer machines, machining centers, milling machines, etc. The purpose of the simulation is to better understand causes of premature support rolling element bearing failures due to grease degradation and corrosion, from the ingress of coolant vapor. Performance characteristics based on coolant vapor in the test chamber, as measured by relative humidity, chamber temperature and chamber pressure relative to the lab atmosphere were obtained for a radial double-lip seal, labyrinth seal, viscoseal/face seal combination and a mechanical face seal. For the operating conditions considered, the best performance was obtained from the viscoseal/face combination followed by the labyrinth seal. 14 refs., 15 figs.

  3. Uncommon or cryptic? Challenges in estimating leopard seal abundance by conventional but state-of-the-art methods

    NASA Astrophysics Data System (ADS)

    Southwell, Colin; Paxton, Charles G. M.; Borchers, David; Boveng, Peter; Rogers, Tracey; de la Mare, William K.

    2008-04-01

    The method traditionally used to estimate pack-ice seal abundance employs sighting surveys from ships or aircraft to estimate the number of seals hauled out on the ice, combined with studies of haul-out behaviour to estimate the proportion of time spent on the ice. Application of this approach has been improved in recent times by developments in survey methodology and satellite technology that theoretically allow biases in the estimation of hauled-out abundance and haul-out behaviour to be accounted for that previously could not be addressed. A survey using these conventional but state-of-the-art methods was undertaken in the summer of 1999/2000 off east Antarctica between longitudes 64°E and 150°E to estimate the abundance of leopard ( Hydrurga leptonyx) and other pack-ice seal species. Because they are either uncommon or very cryptic, very few leopard seals were encountered despite a large survey effort. This presented challenges in both application of the methods and analysis of the data. Abundance estimates were derived using a number of plausible predictive models. The model considered as the most reliable returned best estimates of 7300 and 12,100 for definite and definite plus probable leopard seal sightings, respectively, with 95% confidence intervals of 3700-14,500 and 7100-23,400. These estimates are likely to be negatively biased and should be treated as minimum estimates only.

  4. A magnetic fluid seal for rotary blood pumps: image and computational analyses of behaviors of magnetic fluids.

    PubMed

    Mitamura, Yoshinori; Yano, Tetsuya; Okamoto, Eiji

    2013-01-01

    A magnetic fluid (MF) seal has excellent durability. The performance of an MF seal, however, has been reported to decrease in liquids (several days). We have developed an MF seal that has a shield mechanism. The seal was perfect for 275 days in water. To investigate the effect of a shield, behaviors of MFs in a seal in water were studied both experimentally and computationally. (a) Two kinds of MF seals, one with a shield and one without a shield, were installed in a centrifugal pump. Behaviors of MFs in the seals in water were observed with a video camera and high-speed microscope. In the seal without a shield, the surface of the water in the seal waved and the turbulent flow affected behaviors of the MFs. In contrast, MFs rotated stably in the seal with a shield in water even at high rotational speeds. (b) Computational fluid dynamics analysis revealed that a stationary secondary flow pattern in the seal and small velocity difference between magnetic fluid and water at the interface. These MF behaviors prolonged the life of an MF seal in water. PMID:24109774

  5. The world's northernmost harbour seal population-how many are there?

    PubMed

    Merkel, Benjamin; Lydersen, Christian; Yoccoz, Nigel G; Kovacs, Kit M

    2013-01-01

    This study presents the first abundance estimate for the world's northernmost harbour seal (Phoca vitulina) population, which resides in Svalbard, Norway, based on three digital stereoscopic photographic surveys conducted in 2009 and 2010. The counts from these high resolution 3D images were combined with a novel method for estimating correction factors for animals that were in the water at the time of the surveys, in which extensive behavioural data from radio-tagged harbour seals were used together with age distribution data to estimate the proportion of seals of various age and sex classes hauled out at the times of the surveys. To detect possible seasonal shifts in age distribution between surveys, lengths of hauled out seals were measured from the stereoscopic images. No body-length differences were detected between the surveys; but, this may be due to a high degree of sexual dimorphism exhibited in this population. Applying the modelled correction factors, a total of 1888 (95% CI: 1660-3023), 1742 (1381-3549) and 1812 (1656-4418) harbour seals were estimated for the surveys flown on 01 August 2009, 01 August 2010 and 19 August 2010, respectively. The similarity between the three survey estimates (despite significant differences in the number of animals actually counted on the photos from each survey effort) suggests that the variation in numbers of hauled out seals is reasonably accurately adjusted for by the haul-out probability model. The low population size, the limited spatial distribution of the population and its reduced genetic diversity make this population vulnerable to chance events, such as disease epidemics. PMID:23844035

  6. Do crabeater seals forage cooperatively?

    NASA Astrophysics Data System (ADS)

    Gales, Nicholas J.; Fraser, William R.; Costa, Daniel P.; Southwell, Colin

    2004-08-01

    Crabeater seals are abundant pack-ice predators that feed almost exclusively on krill. They have a circumpolar distribution and are generally sighted hauled out on ice floes alone or in pairs. Here we report our observations of a sighting of 150-200 crabeater seals, which were synchronised in their diving and surfacing behaviour, along with a summary of similar observations from western Antarctica of large groups of crabeater seals in synchronous dive cycles. We report on the low frequency of sightings of such groups during Antarctic pack-ice seal surveys in eastern (Greater) Antarctica. We examine plausible hypotheses to explain these observations, and suggest this behaviour is likely to represent some form of cooperative foraging behaviour, whereby a net advantage in individual energy intake rates is conferred to each seal. Current research on crabeater seal foraging using satellite-linked dive recorders is unlikely to provide sufficiently fine-scale data to examine this hypothesis. Nor will this approach indicate if a seal is foraging with conspecifics. The use of remote or animal-borne camera systems is more likely to provide an insight into fine-scale foraging tactics, as well as the possible, occasional use of cooperative foraging strategies.

  7. Transient thermal-mechanical coupling behavior analysis of mechanical seals during start-up operation

    NASA Astrophysics Data System (ADS)

    Gao, B. C.; Meng, X. K.; Shen, M. X.; Peng, X. D.

    2016-05-01

    A transient thermal-mechanical coupling model for a contacting mechanical seal during start-up has been developed. It takes into consideration the coupling relationship among thermal-mechanical deformation, film thickness, temperature and heat generation. The finite element method and multi-iteration technology are applied to solve the temperature distribution and thermal-mechanical deformation as well as their evolution behavior. Results show that the seal gap transforms from negative coning to positive coning and the contact area of the mechanical seal gradually decreases during start-up. The location of the maximum temperature and maximum contact pressure move from the outer diameter to inside diameter. The heat generation and the friction torque increase sharply at first and then decrease. Meanwhile, the contact force decreases and the fluid film force and leakage rate increase.

  8. Measuring hearing in the harbor seal (Phoca vitulina): Comparison of behavioral and auditory brainstem response techniques

    NASA Astrophysics Data System (ADS)

    Wolski, Lawrence F.; Anderson, Rindy C.; Bowles, Ann E.; Yochem, Pamela K.

    2003-01-01

    Auditory brainstem response (ABR) and standard behavioral methods were compared by measuring in-air audiograms for an adult female harbor seal (Phoca vitulina). Behavioral audiograms were obtained using two techniques: the method of constant stimuli and the staircase method. Sensitivity was tested from 0.250 to 30 kHz. The seal showed good sensitivity from 6 to 12 kHz [best sensitivity 8.1 dB (re 20 μPa2.s) RMS at 8 kHz]. The staircase method yielded thresholds that were lower by 10 dB on average than the method of constant stimuli. ABRs were recorded at 2, 4, 8, 16, and 22 kHz and showed a similar best range (8-16 kHz). ABR thresholds averaged 5.7 dB higher than behavioral thresholds at 2, 4, and 8 kHz. ABRs were at least 7 dB lower at 16 kHz, and approximately 3 dB higher at 22 kHz. The better sensitivity of ABRs at higher frequencies could have reflected differences in the seal's behavior during ABR testing and/or bandwidth characteristics of test stimuli. These results agree with comparisons of ABR and behavioral methods performed in other recent studies and indicate that ABR methods represent a good alternative for estimating hearing range and sensitivity in pinnipeds, particularly when time is a critical factor and animals are untrained.

  9. Fine-scale habitat selection of crabeater seals as determined by diving behavior

    NASA Astrophysics Data System (ADS)

    Burns, J. M.; Hindell, M. A.; Bradshaw, C. J. A.; Costa, D. P.

    2008-02-01

    Previous studies within the Marguerite Bay region of the Antarctic Peninsula (˜67°S, ˜67°W) demonstrated that during winter, crabeater seals ( Lobodon carcinophagus) were not randomly distributed across available habitat, but instead were more likely to be located in nearshore waters where bathymetric gradients and ice concentrations were high. Here, we investigate how the diving patterns of crabeater seals vary in response to these habitat characteristics, and interpret seal behaviors in light of information on the distribution of their primary prey, krill ( Euphausia superba or Euphausia crystallorophias). Diving and movement patterns were obtained from 34 seals (16 male, 18 female) fitted with satellite-relayed data loggers (SRDLs) during the 2001 and 2002 Southern Ocean GLOBEC cruises. Tags transmitted position and dive information for 4-174 days, during which time we received an average of 21 positions/day, and information on a total of 124,681 dives. A series of generalized linear mixed-effect models (GLMM) were used to evaluate the relationship between diving behavior and temporal and physical features of the habitat, and models contrasted using AIC c and BIC weights. Overall, we found that the most parsimonious models included year, month, and period (day, dusk, night). In general, seals dived deeper (158 vs. 73 m) and longer (432 vs. 360 s) during the day than at night. In addition, daytime dives included slightly more time at the foraging depths (142 vs. 102 s), and were slightly more efficient (24% vs. 21% of the dive cycle spent at the bottom). When dive patterns were examined with respect to bathymetry, models indicated that seals were foraging in shallower waters (366 vs. 410 m) and closer to the bottom (dives were 50.3% vs. 26.3% of bathymetric depth) during the day than at night. In combination, these findings suggest that crabeater seals foraging during the day exploited zooplankton schools compressed along the bottom. At night, when

  10. Corrosion Behavior of an Abradable Seal Coating System

    NASA Astrophysics Data System (ADS)

    Zhang, Feng; Xu, Cunguan; Lan, Hao; Huang, Chuanbing; Zhou, Yang; Du, Lingzhong; Zhang, Weigang

    2014-08-01

    A novel NiTi/BN composite abradable coating and two traditional Ni/C and Ni/BN coatings were manufactured with NiAl as the bond layer using thermal spray technology and their corrosion behaviors were investigated. In salt spray corrosion testing of the Ni/BN coating, defective sites of the metal matrix were corroded preferentially. Simulated occlusion experiments and electrochemical tests indicated that migration of ions resulted in pH decrease and Cl- enrichment in defects, and a more aggressive electrolyte led to a decrease of the corrosion potential of the metal inside defects but an increase of the corrosion current density, representing an autocatalytic corrosion process. Moreover, galvanic corrosion between the top and bond coatings of the abradable system was studied via the electrochemical technique. The results showed that, for the NiTi/BN, Ni/BN, and Ni/graphite coatings with a NiAl bond coating, current flow was generated between the anode and cathode. The NiTi/BN coating acted as the cathode due to its passivation, while the Ni/BN and Ni/graphite coatings acted as the anode because of their lower corrosion potential compared with the NiAl coating. The anode suffered serious corrosion damage due to galvanic corrosion, while the cathode corroded only slightly.

  11. AGING BEHAVIOR OF VITON O-RING SEALS IN THE 9975 SHIPPING PACKAGE

    SciTech Connect

    Skidmore, E.; Daugherty, W.; Hoffman, E.; Dunn, K.; Bellamy, S.

    2012-01-13

    The Savannah River Site (SRS) is storing plutonium (Pu) materials in the K-Area Materials Storage (KAMS) facility. The Pu materials were packaged according to the DOE-STD-3013 standard and shipped to the SRS in Type B 9975 packages. The robust 9975 shipping package was not designed for long-term product storage, but it is a specified part of the storage configuration and the KAMS facility safety basis credits the 9975 design with containment. Within the 9975 package, nested stainless steel containment vessels are closed with dual O-ring seals based on Viton{reg_sign} GLT or GLT-S fluoroelastomer. The aging behavior of the O-ring compounds is being studied to provide the facility with advanced notice of nonconformance and to develop life prediction models. A combination of field surveillance, leak testing of surrogate fixtures aged at bounding service temperatures, and accelerated-aging methodologies based on compression stress-relaxation and oxygen consumption analysis is being used to evaluate seal performance. A summary of the surveillance program relative to seal aging behavior is presented.

  12. Behavior associated with forced copulation of juvenile Pacific harbor seals (Phoca vitulina richardsi) by southern sea otters (Enhydra lutris nereis)

    USGS Publications Warehouse

    Harris, Heather S.; Oates, Stori C.; Staedler, Michelle M.; Tinker, M. Tim; Jessup, David A.; Harvey, James T.; Miller, Melissa A.

    2010-01-01

    Nineteen occurrences of interspecific sexual behavior between male southern sea otters (Enhydra lutris nereis) and juvenile Pacific harbor seals (Phoca vitulina richardsi) were reported in Monterey Bay, California, between 2000 and 2002. At least three different male sea otters were observed harassing, dragging, guarding, and copulating with harbor seals for up to 7 d postmortem. Carcasses of 15 juvenile harbor seals were recovered, and seven were necropsied in detail by a veterinary pathologist. Necropsy findings from two female sea otters that were recovered dead from male sea otters exhibiting similar behavior are also presented to facilitate a comparison of lesions. The most frequent lesions included superficial skin lacerations; hemorrhage around the nose, eyes, flippers, and perineum; and traumatic corneal erosions or ulcers. The harbor seals sustained severe genital trauma, ranging from vaginal perforation to vagino-cervical transection, and colorectal perforations as a result of penile penetration. One harbor seal developed severe pneumoperitoneum subsequent to vaginal perforation, which was also observed in both female sea otters and has been reported as a postcoital lesion in humans. This study represents the first description of lesions resulting from forced copulation of harbor seals by sea otters and is also the first report of pneu-moperitoneum secondary to forced copulation in a nonhuman animal. Possible explanations for this behavior are discussed in the context of sea otter biology and population demographics.

  13. Habitat Selection and Foraging Behavior of Southern Elephant Seals in the Western Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Huckstadt, L.; Costa, D. P.; McDonald, B. I.; Tremblay, Y.; Crocker, D. E.; Goebel, M. E.; Fedak, M. E.

    2006-12-01

    We examined the foraging behavior of 18 southern elephant seals foraging over two seasons in the Western Antarctic Peninsula. The foraging behavior and habitat utilization of 7 females in 2005 and 12 in 2006 were followed using satellite linked Satellite Relay Data Loggers that measured diving behavior as well collected salinity and temperature profiles as the animals dove. Animals were tagged after the annual molt during February at Cape Shirreff Livngston Island, South Shetland Islands. There was significant interannual variation in the regions of the Southern Ocean used by seals from Livingston Island. In 2005 of the 7 animals tagged one foraged 4700 km due west of the Antarctic Peninsula going as far as 150 W. The remaining females headed south along the Western Antarctic Peninsula bypassing Marguerite Bay moving south along Alexander Island. Three of these animals continued to forage in the pack ice as it developed. On their return trip all females swam past Livingston Island, continuing on to South Georgia Island where they apparently bred in the austral spring. One animal returned to Cape Shirreff to molt and her tag was recovered. During 2006 animals initially followed a similar migratory pattern going south along the Antarctic Peninsula, but unlike 2005 where the majority of the animals remained in the immediate vicinity of the Western Antarctic Peninsula, most of the animals in 2006 moved well to the west foraging as far as the Amundsen Sea. We compared the area restricted search (focal foraging areas) areas of these animals using a newly developed fractal landscape technique that identifies and quantifies areas of intensive search. The fractal analysis of area restricted search shows that the area, distance and coverage (Fractal D) searched were not different between years, while the time spent in the search areas was higher in 2005. Further analysis will examine how the physical properties of the water column as determined from the CTD data derived from

  14. Seals and Sealing Techniques

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Developments by the aerospace industry in seals and sealing techniques are announced for possible use in other areas. The announcements presented are grouped as: sealing techniques for cryogenic fluids, high pressure applications, and modification for improved performance.

  15. Spatially Estimating Disturbance of Harbor Seals (Phoca vitulina)

    PubMed Central

    Jansen, John K.; Brady, Gavin M.; Ver Hoef, Jay M.; Boveng, Peter L.

    2015-01-01

    Tidewater glacial fjords in Alaska provide habitat for some of the largest aggregations of harbor seals (Phoca vitulina), with calved ice serving as platforms for birthing and nursing pups, molting, and resting. These fjords have also been popular destinations for tour ships for more than a century, with dramatic increases in vessel traffic since the 1980s. Seals on ice are known to flush into the water when approached by tour ships, but estimating the exposure to disturbance across populations is difficult. Using aerial transect sampling while simultaneously tracking vessel movements, we estimated the spatial overlap between seals on ice and cruise ships in Disenchantment Bay, Alaska, USA. By integrating previously estimated rates of disturbance as a function of distance with an ‘intensity surface’ modeled spatially from seal locations in the surveys, we calculated probabilities of seals flushing during three separate ship visits. By combining our estimate of seals flushed with a modeled estimate of the total fjord population, we predict that up to 14% of the seals (up to 11% of pups) hauled out would have flushed into the water, depending on the route taken by ships relative to seal aggregations. Such high potential for broad-scale disturbance by single vessels (when up to 4 ships visit per day) was unexpected and underscores the need to 1) better understand long-term effects of disturbance; 2) regularly monitor populations exposed to high vessel traffic; and 3) develop conservation measures to reduce seal-ship overlap. PMID:26132083

  16. Aging Behavior of Viton{sup R} O-Ring Seals in the 9975 Shipping Package - 12594

    SciTech Connect

    Skidmore, T. Eric; Daugherty, William L.; Hoffman, Elizabeth N.; Dunn, Kerry A.; Stephen Bellamy, J.; Shuler, James M.

    2012-07-01

    The Savannah River Site (SRS) is storing plutonium (Pu) materials in the K-Area Materials Storage (KAMS) facility. The Pu materials were packaged according to the DOE-STD-3013 standard and shipped to the SRS in Type B 9975 packages. The robust 9975 shipping package was not designed for long-term product storage, but it is a specified part of the storage configuration and the KAMS facility safety basis credits the 9975 design with containment. Within the 9975 package, nested stainless steel containment vessels are closed with dual O-ring seals based on Viton{sup R} GLT or GLT-S fluoro-elastomer. The aging behavior of the O-ring compounds is being studied to provide the facility with advanced notice of nonconformance and to develop life prediction models. A combination of field surveillance, leak testing of surrogate fixtures aged at bounding service temperatures, and accelerated-aging methodologies based on compression stress-relaxation and oxygen consumption analysis is being used to evaluate seal performance. A summary of the surveillance program relative to seal aging behavior is presented. The aging behavior of fluoro-elastomer seals based on Viton{sup R} GLT and GLT-S is being studied to develop life prediction models in support of long-term storage of plutonium materials in the 9975 shipping packages at the Savannah River Site. Field surveillance data in combination with accelerated-aging data suggest a significant lifetime for the seals. Typical storage conditions are not anticipated to challenge the leak-tightness of the seals for many years. Early life prediction models based on compression stress relaxation indicate a seal lifetime of ∼12 years at the maximum service temperature predicted (93 deg. C). Seal lifetimes at lower, more realistic conditions are likely significantly longer. Service life predictions based on CSR data are thus far conservative relative to predictions based on time to leakage failure. Surveillance data on packages examined after 6

  17. Some new results concerning the dynamic behavior of annular turbulent seals

    NASA Technical Reports Server (NTRS)

    Massmann, H.; Nordmann, R.

    1985-01-01

    The dynamic characteristics of annular turbulent seals applied in high pressure turbopumps can be described by stiffness, damping, and inertia coefficients. An improved procedure is presented for determining these parameters by using measurements made with newly developed test equipment. The dynamic system seal, consisting of the fluid between the cylindrical surfaces of the rotating shaft and the housing, is excited by test forces (input), and the relative motion between the surfaces (output) is measured. Transformation of the input and output time signals into the frequency domain leads to frequency response functions. An analytical model, depending on the seal parameters, is fitted to the measured data in order to identify the dynamic coefficients. Some new results are reported that show the dependencies of these coefficients with respect to the axial and radial Reynolds numbers and the geometrical data of the seal.

  18. Novel Silver/mica Multilayer Compressive Seals for Solid Oxide Fuel Cells: The Effect of Thermal Cycling and Material Degradation on Leak Behavior

    SciTech Connect

    Chou, Y. S.; Stevenson, Jeffry W.

    2003-09-01

    A novel Ag/mica compressive seal was thermally cycled between 100 degrees C and 800 degrees C in air to evaluate its stability. The novel Ag/mica compressive seal was composed of a naturally cleaved Muscovite mica sheet and two thin silver layers, and was reported in a previous study to have very low leak rates at 800 degrees C. In the present study, we examined the thermal cycle stability of the Ag/mica-based compressive seals pressed between mating couples with large and small mismatch in thermal expansion. For comparison, thermal cycling was also conducted on plain mica as well as plain silver only. In addition, the results were compared with published data of a similar mica seal using glass instead of Ag as the interlayers. For mating materials of large mismatch in CTE (Inconel/alumina), the Ag/mica seal showed lower leak rates than the plain mica. For mating materials of small mismatch in CTE (SS430/alumina), the leak rates were similar for both the Ag/mica and the plain mica seal. Scanning electron microscopy was used to characterize the microstructure of the mica after thermal cycling. Microcracks, fragmentation, and wear particle formation were observed on the mica and were correlated to the leak behavior. Overall, the novel Ag/mica seals present good thermal cycle stability for solid oxide fuel cells although the leak rates were greater than the corresponding mica seals with glass interlayers.

  19. Seasonal Activity Budget of Adult Baltic Ringed Seals

    PubMed Central

    Harkonen, Tero; Jüssi, Mart; Jüssi, Ivar; Verevkin, Michail; Dmitrieva, Lilia; Helle, Eero; Sagitov, Roustam; Harding, Karin C.

    2008-01-01

    Although ringed seals are important components in oceanic and fresh water ecosystems at high latitudes, little is known about how they exploit these harsh environments. Seasonal activity and diving behaviour of 19 adult Baltic ringed seals were studied by satellite telemetry. We elaborated an activity budget for ten months of the year, extending over the period from moult to the breeding season. Seals from three main regions showed explicit site fidelity and the distributions of animals tagged from different areas did not overlap, suggesting separate stocks. Both the mean duration and the mean depth of dives peaked in June and July. Seals spent 70% (females) to 85% (males) of their time diving in June and July which decreased to 50% in late autumn. Less than one percent of dives exceeded 10 min in females, while 10% of male dives lasted longer than 10 min in June to September. Less than one percent of dives lasted for more than 25 min. Both females and males were most active during day time and hauled out predominantly during the night. Activity patterns during the summer are suggested to be correlated to energy accumulation and prey availability. The information on seasonal activity budget is crucial for developing population energetic models where interactions between ringed seals and other trophic levels can be evaluated. PMID:18414676

  20. Lesions and behavior associated with forced copulation of juvenile Pacific harbor seals (Phoca vitulina richardsi) by southern sea otters (Enhydra lutris nereis)

    USGS Publications Warehouse

    Harris, H.S.; Oates, S.C.; Staedler, M.M.; Tinker, M.T.; Jessup, David A.; Harvey, J.T.; Miller, M.A.

    2010-01-01

    Nineteen occurrences of interspecific sexual behavior between male southern sea otters (Enhydra lutris nereis) and juvenile Pacific harbor seals (Phoca vitulina richardsi) were reported in Monterey Bay, California, between 2000 and 2002. At least three different male sea otters were observed harassing, dragging, guarding, and copulating with harbor seals for up to 7 d postmortem. Carcasses of 15 juvenile harbor seals were recovered, and seven were necropsied in detail by a veterinary pathologist. Necropsy findings from two female sea otters that were recovered dead from male sea otters exhibiting similar behavior are also presented to facilitate a comparison of lesions. The most frequent lesions included superficial skin lacerations; hemorrhage around the nose, eyes, flippers, and perineum; and traumatic corneal erosions or ulcers. The harbor seals sustained severe genital trauma, ranging from vaginal perforation to vagino-cervical transection, and colorectal perforations as a result of penile penetration. One harbor seal developed severe pneumoperitoneum subsequent to vaginal perforation, which was also observed in both female sea otters and has been reported as a postcoital lesion in humans. This study represents the first description of lesions resulting from forced copulation of harbor seals by sea otters and is also the first report of pneumoperitoneum secondary to forced copulation in a nonhuman animal. Possible explanations for this behavior are discussed in the context of sea otter biology and population demographics.

  1. Influence of the microstructure of ceramic materials on their wear behavior in mechanical seals

    SciTech Connect

    Wallis, R.

    1994-10-01

    Ceramic materials such as aluminium oxide and silicon carbide are regularly used as one of the counterfaces to oppose carbon graphite in a mechanical seal. Under nominally identical test conditions, the same carbon graphite face can show high wear rates against a material from one supplier but a significantly lower wear rate on a similar material from another. The general descriptions of aluminium oxide and silicon carbide can cover significant differences in properties between materials from various suppliers. Ceramic counterfaces from several manufacturers have been examined, after testing under similar conditions, in order to understand the microstructural factors that influence the wear of the carbon graphite and hence the lift of the mechanical seal. There is evidence to suggest that the wear resistance of the system depends on the grain size distribution, the integrity of the grain bonding and the presence of additional phases. 13 refs., 15 figs., 1 tab.

  2. Static and Dynamic Friction Behavior of Candidate High Temperature Airframe Seal Materials

    NASA Technical Reports Server (NTRS)

    Dellacorte, C.; Lukaszewicz, V.; Morris, D. E.; Steinetz, B. M.

    1994-01-01

    The following report describes a series of research tests to evaluate candidate high temperature materials for static to moderately dynamic hypersonic airframe seals. Pin-on-disk reciprocating sliding tests were conducted from 25 to 843 C in air and hydrogen containing inert atmospheres. Friction, both dynamic and static, was monitored and serves as the primary test measurement. In general, soft coatings lead to excessive static friction and temperature affected friction in air environments only.

  3. Habitat-Mediated Dive Behavior in Free-Ranging Grey Seals

    PubMed Central

    Jessopp, Mark; Cronin, Michelle; Hart, Tom

    2013-01-01

    Understanding the links between foraging behaviour and habitat use of key species is essential to addressing fundamental questions about trophic interactions and ecosystem functioning. Eight female grey seals (Halichoerus grypus) were equipped with time-depth recorders linked to Fastloc GPS tags following the annual moult in southwest Ireland. Individual dives were coupled with environmental correlates to investigate the habitat use and dive behaviour of free-ranging seals. Dives were characterised as either pelagic, benthic, or shallow (where errors in location and charted water depth made differentiating between pelagic and benthic dives unreliable). Sixty-nine percent of dives occurring in water >50 m were benthic. Pelagic dives were more common at night than during the day. Seals performed more pelagic dives over fine sediments (mud/sand), and more benthic dives when foraging over more three-dimensionally complex rock substrates. We used Markov chain analysis to determine the probability of transiting between dive states. A low probability of repeat pelagic dives suggests that pelagic prey were encountered en route to the seabed. This approach could be applied to make more accurate predictions of habitat use in data-poor areas, and investigate contentious issues such as resource overlap and competition between top predators and fisheries, essential for the effective conservation of these key marine species. PMID:23667663

  4. Fluid sealing

    SciTech Connect

    Nau, B.S.

    1987-01-01

    This book contains 41 papers. Some of the titles are: Evaluation of secondary containment seals for pumps on hydrocarbon duties; Valve steam sealing in nuclear plants; Design directives for liquid spattered labyrinth seals; Analysis of a novel rotary seal; Contacting mechanical seal design using a simplified hydrostatic model; and Transient thermoelastic effects in a mechanical face.

  5. Acoustic Seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor)

    2006-01-01

    The invention relates to a sealing device having an acoustic resonator. The acoustic resonator is adapted to create acoustic waveforms to generate a sealing pressure barrier blocking fluid flow from a high pressure area to a lower pressure area. The sealing device permits noncontacting sealing operation. The sealing device may include a resonant-macrosonic-synthesis (RMS) resonator.

  6. Acoustic seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor)

    2006-01-01

    The invention relates to a sealing device having an acoustic resonator. The acoustic resonator is adapted to create acoustic waveforms to generate a sealing pressure barrier blocking fluid flow from a high pressure area to a lower pressure area. The sealing device permits noncontacting sealing operation. The sealing device may include a resonant-macrosonic-synthesis (RMS) resonator.

  7. Likely effects of construction of Scroby Sands offshore wind farm on a mixed population of harbour Phoca vitulina and grey Halichoerus grypus seals.

    PubMed

    Skeate, Eleanor R; Perrow, Martin R; Gilroy, James J

    2012-04-01

    Scroby Sands offshore wind farm was built close to a haul-out and breeding site for harbour seal, a species of conservation concern. An aerial survey programme conducted during a five-year period spanning wind farm construction, revealed a significant post-construction decline in haul-out counts. Multivariate model selection suggested that the decline was not related to the environmental factors considered, nor did it mirror wider population trends. Although cause and effect could not be unequivocally established, the theoretical basis of hearing in pinnipeds and previous studies suggested that extreme noise (to 257 dB re 1 μ Pa(pp) @ 1m) generated by pile-driving of turbine bases led to displacement of seals. A lack of full recovery of harbour seal during the study was also linked to their sensitivity to vessel activity and/or rapid colonisation of competing grey seal. Any impact of offshore wind farm development upon pinnipeds would be much reduced without pile-driving. PMID:22333892

  8. Fortuitous Encounters between Seagliders and Adult Female Northern Fur Seals (Callorhinus ursinus) off the Washington (USA) Coast: Upper Ocean Variability and Links to Top Predator Behavior

    PubMed Central

    Pelland, Noel A.; Sterling, Jeremy T.; Lea, Mary-Anne; Bond, Nicholas A.; Ream, Rolf R.; Lee, Craig M.; Eriksen, Charles C.

    2014-01-01

    Behavioral responses by top marine predators to oceanographic features such as eddies, river plumes, storms, and coastal topography suggest that biophysical interactions in these zones affect predators' prey, foraging behaviors, and potentially fitness. However, examining these pathways is challenged by the obstacles inherent in obtaining simultaneous observations of surface and subsurface environmental fields and predator behavior. In this study, migratory movements and, in some cases, diving behavior of 40 adult female northern fur seals (NFS; Callorhinus ursinus) were quantified across their range and compared to remotely-sensed environmental data in the Gulf of Alaska and California Current ecosystems, with a particular focus off the coast of Washington State (USA) – a known foraging ground for adult female NFS and where autonomous glider sampling allowed opportunistic comparison of seal behavior to subsurface biophysical measurements. The results show that in these ecosystems, adult female habitat utilization was concentrated near prominent coastal topographic, riverine, or inlet features and within 200 km of the continental shelf break. Seal dive depths, in most ecosystems, were moderated by surface light level (solar or lunar), mirroring known behaviors of diel vertically-migrating prey. However, seal dives differed in the California Current ecosystem due to a shift to more daytime diving concentrated at or below the surface mixed layer base. Seal movement models indicate behavioral responses to season, ecosystem, and surface wind speeds; individuals also responded to mesoscale eddies, jets, and the Columbia River plume. Foraging within small scale surface features is consistent with utilization of the inner coastal transition zone and habitats near coastal capes, which are known eddy and filament generation sites. These results contribute to our knowledge of NFS migratory patterns by demonstrating surface and subsurface behavioral responses to a spatially

  9. Fortuitous encounters between seagliders and adult female northern fur seals (Callorhinus ursinus) off the Washington (USA) coast: upper ocean variability and links to top predator behavior.

    PubMed

    Pelland, Noel A; Sterling, Jeremy T; Lea, Mary-Anne; Bond, Nicholas A; Ream, Rolf R; Lee, Craig M; Eriksen, Charles C

    2014-01-01

    Behavioral responses by top marine predators to oceanographic features such as eddies, river plumes, storms, and coastal topography suggest that biophysical interactions in these zones affect predators' prey, foraging behaviors, and potentially fitness. However, examining these pathways is challenged by the obstacles inherent in obtaining simultaneous observations of surface and subsurface environmental fields and predator behavior. In this study, migratory movements and, in some cases, diving behavior of 40 adult female northern fur seals (NFS; Callorhinus ursinus) were quantified across their range and compared to remotely-sensed environmental data in the Gulf of Alaska and California Current ecosystems, with a particular focus off the coast of Washington State (USA)--a known foraging ground for adult female NFS and where autonomous glider sampling allowed opportunistic comparison of seal behavior to subsurface biophysical measurements. The results show that in these ecosystems, adult female habitat utilization was concentrated near prominent coastal topographic, riverine, or inlet features and within 200 km of the continental shelf break. Seal dive depths, in most ecosystems, were moderated by surface light level (solar or lunar), mirroring known behaviors of diel vertically-migrating prey. However, seal dives differed in the California Current ecosystem due to a shift to more daytime diving concentrated at or below the surface mixed layer base. Seal movement models indicate behavioral responses to season, ecosystem, and surface wind speeds; individuals also responded to mesoscale eddies, jets, and the Columbia River plume. Foraging within small scale surface features is consistent with utilization of the inner coastal transition zone and habitats near coastal capes, which are known eddy and filament generation sites. These results contribute to our knowledge of NFS migratory patterns by demonstrating surface and subsurface behavioral responses to a spatially

  10. Seals, seal trainers, and mycobacterial infection.

    PubMed

    Thompson, P J; Cousins, D V; Gow, B L; Collins, D M; Williamson, B H; Dagnia, H T

    1993-01-01

    In 1986, three seals died in a marine park in Western Australia; culture of postmortem tissue suggested infection with Mycobacterium bovis. In 1988, a seal trainer who had been employed at the Western Australian marine park until 1985 developed pulmonary tuberculosis caused by M. bovis while working in a zoo 3,000 km away on the east coast of Australia. Culture characteristics, biochemical behavior, sodium dodecyl sulphate polyacrylamide gel electrophoresis, and restriction endonuclease analysis suggested that the strains of M. bovis infecting the seals and trainer were identical but unique and differed from reference strains and local cattle strains of M. bovis. The infection in both the seals and the trainer had a destructive but indolent course. This is the first time that M. bovis has been observed in seals and the first time that tuberculous infection has been documented to be transmitted from seals to humans. Further investigation of the extent of tuberculous infection in seal populations elsewhere in the world seems warranted, and those working with seals and other marine animals should be monitored for infection. PMID:8420412

  11. Glass sealing

    SciTech Connect

    Brow, R.K.; Kovacic, L.; Chambers, R.S.

    1996-04-01

    Hernetic glass sealing technologies developed for weapons component applications can be utilized for the design and manufacture of fuel cells. Design and processing of of a seal are optimized through an integrated approach based on glass composition research, finite element analysis, and sealing process definition. Glass sealing procedures are selected to accommodate the limits imposed by glass composition and predicted calculations.

  12. Sealing device

    SciTech Connect

    Garcia-Crespo, Andres Jose

    2013-12-10

    A sealing device for sealing a gap between a dovetail of a bucket assembly and a rotor wheel is disclosed. The sealing device includes a cover plate configured to cover the gap and a retention member protruding from the cover plate and configured to engage the dovetail. The sealing device provides a seal against the gap when the bucket assemply is subjected to a centrifugal force.

  13. Coining seal

    DOEpatents

    Mancebo, Lloyd

    1976-01-01

    A bakeable high pressure-vacuum seal is provided in which an inductile sealing element having a butterfly shaped crosssection with protruding sharp edges at each of the four corners, is sandwiched between two ductile sealing elements, the sandwiched assembly then being compressed between the surfaces of the flange elements of a high pressure or high vacuum vessel to coin the ductile sealing element into the surface of the inductile sealing element as well as the surfaces of the flange elements.

  14. Foraging Behavior of Subantarctic Fur Seals Supports Efficiency of a Marine Reserve's Design.

    PubMed

    Kirkman, Stephen P; Yemane, Dawit G; Lamont, Tarron; Meÿer, Michael A; Pistorius, Pierre A

    2016-01-01

    Foraging behaviour of marine top predators is increasingly being used to identify areas of ecological importance. This is largely enabled by the ability of many such species to forage extensively in search of prey that is often concentrated in oceanographically productive areas. To identify important habitat in the Southern Indian Ocean within and around South Africa's Prince Edward Islands' Marine Protected Area (MPA), satellite transmitters were deployed on 12 lactating Subantarctic fur seals Arctocephalus tropicalis at Prince Edward Island (PEI) itself. Switching state space models were employed to correct ARGOS tracks and estimate behavioural states for locations along predicted tracks, namely travelling or area restricted search (ARS). A random forest model showed that distance from the study colony, longitude and distance from the Subantarctic Front were the most important predictors of suitable foraging habitat (inferred from ARS). Model-predicted suitable habitat occurred within the MPA in relatively close access to the colony during summer and autumn, but shifted northwards concurrently with frontal movements in winter and spring. The association of ARS with the MPA during summer-autumn was highly significant, highlighting the effectiveness of the recently declared reserve's design for capturing suitable foraging habitat for this and probably other marine top predator species. PMID:27163373

  15. Pore networks in continental and marine mudstones: Characteristics and controls on sealing behavior

    USGS Publications Warehouse

    Heath, J.E.; Dewers, T.A.; McPherson, B.J.O.L.; Petrusak, R.; Chidsey, T.C.; Rinehart, A.J.; Mozley, P.S.

    2011-01-01

    Mudstone pore networks are strong modifiers of sedimentary basin fluid dynamics and have a critical role in the distribution of hydrocarbons and containment of injected fluids. Using core samples from continental and marine mudstones, we investigate properties of pore types and networks from a variety of geologic environments, together with estimates of capillary beam- scanning electron microscopy, suggest seven dominant mudstone pore types distinguished by geometry and connectivity. A dominant planar pore type occurs in all investigated mudstones and generally has high coordination numbers (i.e., number of neighboring connected pores). Connected networks of pores of this type contribute to high mercury capillary pressures due to small pore throats at the junctions of connected pores and likely control most matrix transport in these mudstones. Other pore types are related to authigenic (e.g., replacement or pore-lining precipitation) clay minerals and pyrite nodules; pores in clay packets adjacent to larger, more competent clastic grains; pores in organic phases; and stylolitic and microfracture-related pores. Pores within regions of authigenic clay minerals often form small isolated networks (<3 ??m). Pores in stringers of organic phases occur as tubular pores or slit- and/or sheet-like pores. These form short, connected lengths in 3D reconstructions, but appear to form networks no larger than a few microns in size. Sealing efficiency of the studied mudstones increases with greater distal depositional environments and greater maximum depth of burial. ?? 2011 Geological Society of America.

  16. Foraging Behavior of Subantarctic Fur Seals Supports Efficiency of a Marine Reserve’s Design

    PubMed Central

    Kirkman, Stephen P.; Yemane, Dawit G.; Lamont, Tarron; Meÿer, Michael A.; Pistorius, Pierre A.

    2016-01-01

    Foraging behaviour of marine top predators is increasingly being used to identify areas of ecological importance. This is largely enabled by the ability of many such species to forage extensively in search of prey that is often concentrated in oceanographically productive areas. To identify important habitat in the Southern Indian Ocean within and around South Africa’s Prince Edward Islands’ Marine Protected Area (MPA), satellite transmitters were deployed on 12 lactating Subantarctic fur seals Arctocephalus tropicalis at Prince Edward Island (PEI) itself. Switching state space models were employed to correct ARGOS tracks and estimate behavioural states for locations along predicted tracks, namely travelling or area restricted search (ARS). A random forest model showed that distance from the study colony, longitude and distance from the Subantarctic Front were the most important predictors of suitable foraging habitat (inferred from ARS). Model-predicted suitable habitat occurred within the MPA in relatively close access to the colony during summer and autumn, but shifted northwards concurrently with frontal movements in winter and spring. The association of ARS with the MPA during summer-autumn was highly significant, highlighting the effectiveness of the recently declared reserve’s design for capturing suitable foraging habitat for this and probably other marine top predator species. PMID:27163373

  17. Ecological, morphological, and molecular studies of Acanthocheilonema odendhali (Nematoda: Filarioidea) in northern fur seals (Callorhinus ursinus) on St. Paul Island, Alaska.

    PubMed

    Kuzmina, T A; Kuzmin, Y I; Tkach, V V; Spraker, T R; Lyons, E T

    2013-09-01

    Studies of northern fur seal (Callorhinus ursinus Linnaeus, 1758) infection by the filariid nematode Acanthocheilonema odendhali were carried out in 2011-2012 on St. Paul Island, Pribilof Archipelago, Alaska. Skins of 502 humanely harvested northern fur seals from haul-out areas of five rookeries, Polovina (n = 122), Morjovi (n = 54), Zapadni (n = 72), Lukanin (n = 109), and Gorbatch (n = 145), were examined. A. odendhali was found in 18% of northern fur seals. The prevalence of infection ranged from 12.5% up to 22.9% on different haul-out areas on the island. The mean intensity of infection was 1.3 (range 1-7). Detailed morphological examination of collected specimens was performed using light microscopy. Several characters were added to the morphological description of the species, among them lateral thickening of the body cuticle, especially prominent in males, variations in number and position of genital papillae in males, transverse striation of the cuticle, and terminal dilation on tail end in microfilariae. The adult specimens studied had a shorter esophagus than type specimens from the California sea lion described by Perry (1967). Comparison of partial sequences of the mitochondrial cox1 gene from specimens collected from five sampling sites on St. Paul Island and a specimen from the type host and territory in California showed no significant differences and strongly supported conspecificity of the material from Alaska with A. odendhali. PMID:23760875

  18. Rotating Brush Seal

    NASA Technical Reports Server (NTRS)

    Lattime, S. B.; Braun, M. J.; Choy. F. K.; Hendricks, R. C.; Steinetz, B. M.

    2006-01-01

    The proven technology of brush seals has been extended to the mitigation of problems arising from friction and wear at the bristle-rotor interface at high surface speeds. In prototype testing, the brush is mounted on, and free to rotate with the shaft, thus providing a complaint primary seal. A face seal positioned between the backing plate of the brush seal and the housing provides a secondary seal. The purpose of this paper is to demonstrate the interaction between the brush bristles and the shaft at high surface speeds as well as introduce a numerical model to simulate the bristle behavior. A test facility was constructed to study the effects of centrifugal forces on bristle deflection in a single rotating brush seal. The bristle-rotor interface was observed through a video camera, which utilized a high magnification borescope and a high frequency strobe light source. Rotational speeds of the rotor and the brush seal were measured by a magnetic and optical speed sensor, respectively. Preliminary results with speeds up to 11,000 rpm show no speed differential between the brush seal and rotor, or any instability problems associated with the brush seal. Bristle liftoff from the rotor is successfully captured on video.

  19. Compliant seal development

    NASA Technical Reports Server (NTRS)

    Hendricks, Robert C.

    1993-01-01

    The compliant metallic seal combines the noncontact feature of the labyrinth seal, the low leakage of a mechanical seal, and the compliant nature of the brush seal. It consists of several thin metallic elements or leaves mounted within a ring which is press fit into the housing, and in form, sort of resembles a lip seal sections wiping the shaft. A second set of overlapping cover leaves are placed on top of the shaft riding leaves which reduces leakage and provides stiffness. The leaves can be straight or angle cut. The shaft riding fingers are designed with mismatched curvature to provide lift off similar to the Rayleigh lift pads in mechanical seals with leading edge clearances nearly twice those of the trailing edge as as shown by Fleming to be optimal for gas flows in convergent seal passages. Leading edge clearances range from 300 to 500 microinches. Balance pockets beneath the leaves provide fluid film feed to the 'Rayleigh lift' surface and the proper balance ratio (mechanical seal) when combined with the static pressure and film pressure. The leaves flex in the radial direction and accommodate thermomechanical behavior as well as axial motion and angular misalignment. In the static mode, there is a net closing force on the leaves. The seals were tested to 70 psi at speeds to 16,000 rpm or surface speeds to 330 fps and temperatures from ambient to 440 F. A slow cycle through the rig critical at 10,000 rpm induced a radial vibration response of 0.004 to 0.005 inch were accommodated by the seal. Preliminary performance data are encouraging demonstrating hydrodynamic liftoff and noncontacting operation at pressure and speeds typical of gas turbine engines. The leakage performance data are significantly better than commercial labyrinth and brush seals which should be expected as this design incorporates the features of the low leakage face or mechanical seal along with the flexibility of the brush configuration.

  20. Compliant seal development

    NASA Astrophysics Data System (ADS)

    Hendricks, Robert C.

    1993-10-01

    The compliant metallic seal combines the noncontact feature of the labyrinth seal, the low leakage of a mechanical seal, and the compliant nature of the brush seal. It consists of several thin metallic elements or leaves mounted within a ring which is press fit into the housing, and in form, sort of resembles a lip seal sections wiping the shaft. A second set of overlapping cover leaves are placed on top of the shaft riding leaves which reduces leakage and provides stiffness. The leaves can be straight or angle cut. The shaft riding fingers are designed with mismatched curvature to provide lift off similar to the Rayleigh lift pads in mechanical seals with leading edge clearances nearly twice those of the trailing edge as as shown by Fleming to be optimal for gas flows in convergent seal passages. Leading edge clearances range from 300 to 500 microinches. Balance pockets beneath the leaves provide fluid film feed to the 'Rayleigh lift' surface and the proper balance ratio (mechanical seal) when combined with the static pressure and film pressure. The leaves flex in the radial direction and accommodate thermomechanical behavior as well as axial motion and angular misalignment. In the static mode, there is a net closing force on the leaves. The seals were tested to 70 psi at speeds to 16,000 rpm or surface speeds to 330 fps and temperatures from ambient to 440 F. A slow cycle through the rig critical at 10,000 rpm induced a radial vibration response of 0.004 to 0.005 inch were accommodated by the seal. Preliminary performance data are encouraging demonstrating hydrodynamic liftoff and noncontacting operation at pressure and speeds typical of gas turbine engines. The leakage performance data are significantly better than commercial labyrinth and brush seals which should be expected as this design incorporates the features of the low leakage face or mechanical seal along with the flexibility of the brush configuration.

  1. Methodological considerations of acoustic playbacks to test the behavioral significance of call directionality in male northern elephant seals (Mirounga angustirostris)

    NASA Astrophysics Data System (ADS)

    Holt, Marla M.; Insley, Stephen J.; Southall, Brandon L.; Schusterman, Ronald J.

    2005-09-01

    While attempting to gain access to receptive females, male northern elephant seals form dominance hierarchies through multiple dyadic interactions involving visual and acoustic signals. These signals are both highly stereotyped and directional. Previous behavioral observations suggested that males attend to the directional cues of these signals. We used in situ vocal playbacks to test whether males attend to directional cues of the acoustic components of a competitors calls (i.e., variation in call spectra and source levels). Here, we will focus on playback methodology. Playback calls were multiple exemplars of a marked dominant male from an isolated area, recorded with a directional microphone and DAT recorder and edited into a natural sequence that controlled call amplitude. Control calls were recordings of ambient rookery sounds with the male calls removed. Subjects were 20 marked males (10 adults and 10 subadults) all located at An~o Nuevo, CA. Playback presentations, calibrated for sound-pressure level, were broadcast at a distance of 7 m from each subject. Most responses were classified into the following categories: visual orientation, postural change, calling, movement toward or away from the loudspeaker, and re-directed aggression. We also investigated developmental, hierarchical, and ambient noise variables that were thought to influence male behavior.

  2. Seal assembly

    NASA Astrophysics Data System (ADS)

    Salt, Jonathan G.; Korzun, Ronald W.; Abbott, David R.

    1993-01-01

    A unitary annular seal structure is provided for attachment to a turbine nozzle in a gas turbine engine. The nozzle includes an annular platform disposed about a longitudinal axis of the engine. An annular array of vanes is secured to the platform. The seal structure includes an abradable annular seal member, a seal backing member, and a seal attachment ring. The ring includes an annular, radially extending, axially acting spring member positioned to cooperate with a plurality of radially extending tabs on the backing member. In use, the seal structure is positioned within a circular opening within the turbine nozzle. The nozzle includes a radially depending appendage formed as part of the nozzle platform. The spring member abuts one side of the appendage and the tabs are positioned to abut another side of the appendage for holding the annular spring member in gas sealing engagement with the appendage to thus provide a seal against gas leakage and to restrain the seal structure axially. The spring member and tabs comprise a radially slideable joint for the seal structure. To restrict circumferential motion of the structure, slots are formed in the appendage for receiving the tabs. The seal is easily replaced by bending the tabs and sliding the seal structure axially out of the nozzle. Differential thermal expansion is accommodated by the slideable seal arrangement.

  3. Distribution, density, and abundance of pack-ice seals in the Amundsen and Ross Seas, Antarctica

    NASA Astrophysics Data System (ADS)

    Bengtson, John L.; Laake, Jeff L.; Boveng, Peter L.; Cameron, Michael F.; Bradley Hanson, M.; Stewart, Brent S.

    2011-05-01

    We made three sets of population surveys of the four species of ice-inhabiting phocid pinnipeds in the Ross and Amundsen Seas between 26 December 1999 and 24 March 2000 using icebreakers and helicopters deployed from those icebreakers. We used line transect methods to survey 23,671 km by helicopter and 3,694 km by ship accounting for a total coverage of 53,217 km 2. We detected and identified 11,308 seals in 7,104 groups and estimated their abundance from estimates of densities using distance sampling methods and corrections for probability of haul out of seals derived from satellite telemetry of tagged seals. Crabeater seals were most abundant (ca 1.7 million) followed by Weddell seals (330,000), Ross seals (22,600), and leopard seals (15,000). Our estimates of abundance are difficult to directly compare with earlier estimates because of geographic areas covered and by our improvements in survey and analytical methods. Notwithstanding these limitations and with some adjustments for differences in methods, we found that our estimates of abundance for crabeater seals are similar to those from the most recent surveys in the Ross and Amundsen Seas and along the George-Oates Coast. Our estimates for Weddell seals are the first for the broad areas of pack ice that we surveyed in the Ross and Amundsen Seas but indicate that these habitats are ecologically important to this species. Our estimates of abundance of Ross seals were relatively similar to estimates for surveys in these areas in the 1970s and 1980s whereas our estimates of abundance of leopard seals were substantially lower.

  4. Security seal

    DOEpatents

    Gobeli, Garth W.

    1985-01-01

    Security for a package or verifying seal in plastic material is provided by a print seal with unique thermally produced imprints in the plastic. If tampering is attempted, the material is irreparably damaged and thus detectable. The pattern of the imprints, similar to "fingerprints" are recorded as a positive identification for the seal, and corresponding recordings made to allow comparison. The integrity of the seal is proved by the comparison of imprint identification records made by laser beam projection.

  5. Turbomachine Sealing

    NASA Technical Reports Server (NTRS)

    Hendricks, Robert C.

    1996-01-01

    Designers and customers are demanding higher performance turbomachine systems that have long life between overhauls and satisfy the more restrictive environmental constraints. This overview provides sources of design data, numerical, and experimental results along with selected new seal configurations and static sealing challenges such as in the combustors. The following categories are presented: (1) Seal Rotordynamic Data Base (experimental analytical program at Texas A&M); (2) Secondary Flow Interactions (validation studies at CFDRC, Huntsville AL); (3) Contact Sealing (selected types with finger seal model); and (4) Environmental Constraints (emphasis on combustors).

  6. Classification and behavior of free-ranging Weddell seal dives based on three-dimensional movements and video-recorded observations

    NASA Astrophysics Data System (ADS)

    Davis, Randall W.; Fuiman, Lee A.; Madden, Kiersten M.; Williams, Terrie M.

    2013-04-01

    The goal of this study was to classify free-ranging (FR) dives of Weddell seals (Leptonychotes weddellii) and to compare them to isolated hole (IH) dives. Classification and comparisons were based on 58 descriptors for three-dimensional dive paths computed from data obtained by attaching video and data recorders to the backs of 12 adult Weddell seals that were free-ranging in eastern McMurdo Sound, Antarctica. We then inferred behavioral functions for the dive classes based on video-recorded observations. Three of the four dive types previously identified from seals diving at an IH occurred in FR seals. Although there were differences associated with location, Types 1, 2 and 3 dives clustered in a similar pattern in the discriminant analysis for FR and IH dives. Most prey (79%) captures occurred during Type 1 dives, and the primary (99%) prey was Antarctic silverfish (Pleuragramma antarcticum). Type 1 dives were the deepest (mean maximum depth 324-378 m), longest in duration (15.0-27.0 min), covered the greatest total distance (1470-2197 m), and had the steepest dive angles (descents: -30°; ascents: +27°). Types 2 and 3 dives formed a continuum from short duration (3.6-7.5 min), shallow (mean maximum depth 30-66 m) dives that were close to the ice hole (farpoint distance 75-130 m) and often involved aggressive interactions with other seals for breathing opportunities (Type 2) to progressively longer (7.9-17.2 min), deeper (mean maximum depth 81-143 m) dives that covered greater total distances (878-1194 m) and were associated with transiting between holes, exploring and occasionally foraging (Type 3). Very long distance Type 4 exploratory dives that were identified in the IH study were completely absent in FR seals.

  7. Seal assembly

    SciTech Connect

    Johnson, Roger Neal; Longfritz, William David

    2001-01-01

    A seal assembly that seals a gap formed by a groove comprises a seal body, a biasing element, and a connection that connects the seal body to the biasing element to form the seal assembly. The seal assembly further comprises a concave-shaped center section and convex-shaped contact portions at each end of the seal body. The biasing element is formed from an elastic material and comprises a convex-shaped center section and concave-shaped biasing zones that are opposed to the convex-shaped contact portions. The biasing element is adapted to be compressed to change a width of the seal assembly from a first width to a second width that is smaller than the first width. In the compressed state, the seal assembly can be disposed in the groove. After release of the compressing force, the seal assembly expands. The contact portions will move toward a surface of the groove and the biasing zones will move into contact with another surface of the groove. The biasing zones will bias the contact portions of the seal body against the surface of the groove.

  8. New insights into the diets of harbor seals in the Salish Sea revealed by quantitative fatty acid signature analysis

    USGS Publications Warehouse

    Bromaghin, Jeffrey F.; Lance, Monique M.; Elliott, Elizabeth W.; Jeffries, Steven J.; Acevedo-Gutiérrez, Alejandro; Kennish, John M.

    2012-01-01

    Harbor seals (Phoca vitulina) are an abundant predator along the west coast of North America, and there is considerable interest in their diet composition, especially in regard to predation on valued fish stocks. Available information on harbor seal diets, primarily derived from scat analysis, suggests that adult salmon (Oncorhynchus spp.), Pacific Herring (Clupea pallasii), and gadids predominate. Because diet assessments based on scat analysis may be biased, we investigated diet composition through quantitative analysis of fatty acid signatures. Blubber samples from 49 harbor seals captured in western North America from haul-outs within the area of the San Juan Islands and southern Strait of Georgia in the Salish Sea were analyzed for fatty acid composition, along with 269 fish and squid specimens representing 27 potential prey classes. Diet estimates varied spatially, demographically, and among individual harbor seals. Findings confirmed the prevalence of previously identified prey species in harbor seal diets, but other species also contributed significantly. In particular, Black (Sebastes melanops) and Yellowtail (S. flavidus) Rockfish were estimated to compose up to 50% of some individual seal diets. Specialization and high predation rates on Black and Yellowtail Rockfish by a subset of harbor seals may play a role in the population dynamics of these regional rockfish stocks that is greater than previously realized.

  9. Seasonal Variation of Harbor Seal's Diet from the Wadden Sea in Relation to Prey Availability.

    PubMed

    de la Vega, Camille; Lebreton, Benoit; Siebert, Ursula; Guillou, Gael; Das, Krishna; Asmus, Ragnhild; Asmus, Harald

    2016-01-01

    The Wadden Sea has an important role for marine mammals in terms of resting, nursing and foraging. Harbor seal is the most abundant marine mammal species in this area. The use of the food resources of the Wadden Sea by seals is not clear, and previous studies showed that this species can travel kilometers away from their haul-outs to forage in the North Sea. In this study, we analyzed the stable isotopes of vibrissae from 23 dead harbor seals found on the island of Sylt to investigate their diet. The predator´s carbon and nitrogen isotope compositions were compared to the compositions of different potential prey items from the Sylt-Rømø Bight and from the North Sea in order to study seasonal pattern in the diet and in the foraging location. In parallel, seasonal variation of abundance and biomass of the potential prey items from the Sylt-Rømø Bight were studied and compare to their contribution to the seal´s diet. The results revealed a change in the seal´s diet from pelagic sources in spring to a benthic based diet in summer, and an increasing use of the North Sea resources in fall and winter in accordance with the seasonal variation of the availability of prey in the Sylt-Rømø Bight. PMID:27176227

  10. Seasonal Variation of Harbor Seal's Diet from the Wadden Sea in Relation to Prey Availability

    PubMed Central

    de la Vega, Camille; Lebreton, Benoit; Siebert, Ursula; Guillou, Gael; Das, Krishna; Asmus, Ragnhild; Asmus, Harald

    2016-01-01

    The Wadden Sea has an important role for marine mammals in terms of resting, nursing and foraging. Harbor seal is the most abundant marine mammal species in this area. The use of the food resources of the Wadden Sea by seals is not clear, and previous studies showed that this species can travel kilometers away from their haul-outs to forage in the North Sea. In this study, we analyzed the stable isotopes of vibrissae from 23 dead harbor seals found on the island of Sylt to investigate their diet. The predator´s carbon and nitrogen isotope compositions were compared to the compositions of different potential prey items from the Sylt-Rømø Bight and from the North Sea in order to study seasonal pattern in the diet and in the foraging location. In parallel, seasonal variation of abundance and biomass of the potential prey items from the Sylt-Rømø Bight were studied and compare to their contribution to the seal´s diet. The results revealed a change in the seal´s diet from pelagic sources in spring to a benthic based diet in summer, and an increasing use of the North Sea resources in fall and winter in accordance with the seasonal variation of the availability of prey in the Sylt-Rømø Bight. PMID:27176227

  11. Nozzle seal

    DOEpatents

    Groff, Russell Dennis; Vatovec, Richard John

    1978-06-11

    In an illustrative embodiment of the invention, a nuclear reactor pressure vessel, having an internal hoop from which the heated coolant emerges from the reactor core and passes through to the reactor outlet nozzles, is provided with annular sealing members operatively disposed between the outlet nozzle and the hoop and partly within a retaining annulus formed in the hoop. The sealing members are biased against the pressure vessel and the hoop and one of the sealing members is provided with a piston type pressure ring sealing member which effectively closes the path between the inlet and outlet coolants in the region about the outlet nozzle establishing a leak-proof condition. Furthermore, the flexible responsiveness of the seal assures that the seal will not structurally couple the hoop to the pressure vessel.

  12. Nozzle seal

    DOEpatents

    Herman, Richard Frederick

    1977-10-25

    In an illustrative embodiment of the invention, a nuclear reactor pressure vessel, having an internal hoop from which the heated coolant emerges from the reactor core and passes through to the reactor outlet nozzles, is provided with sealing members operatively disposed between the outlet nozzle and the hoop. The sealing members are biased against the pressure vessel and the hoop and are connected by a leak restraining member establishing a leak-proof condition between the inlet and outlet coolants in the region about the outlet nozzle. Furthermore, the flexible responsiveness of the seal assures that the seal will not structurally couple the hoop to the pressure vessel.

  13. Brush Seals for Improved Steam Turbine Performance

    NASA Technical Reports Server (NTRS)

    Turnquist, Norman; Chupp, Ray; Baily, Fred; Burnett, Mark; Rivas, Flor; Bowsher, Aaron; Crudgington, Peter

    2006-01-01

    GE Energy has retrofitted brush seals into more than 19 operating steam turbines. Brush seals offer superior leakage control compared to labyrinth seals, owing to their compliant nature and ability to maintain very tight clearances to the rotating shaft. Seal designs have been established for steam turbines ranging in size from 12 MW to over 1200 MW, including fossil, nuclear, combined-cycle and industrial applications. Steam turbines present unique design challenges that must be addressed to ensure that the potential performance benefits of brush seals are realized. Brush seals can have important effects on the overall turbine system that must be taken into account to assure reliable operation. Subscale rig tests are instrumental to understanding seal behavior under simulated steam-turbine operating conditions, prior to installing brush seals in the field. This presentation discusses the technical challenges of designing brush seals for steam turbines; subscale testing; performance benefits of brush seals; overall system effects; and field applications.

  14. Ferrules seals

    DOEpatents

    Smith, James L.

    1984-01-01

    A device is provided for sealing an inner tube and an outer tube without excessively deforming the tubes. The device includes two ferrules which cooperate to form a vacuum-tight seal between the inner tube and outer tube and having mating surfaces such that overtightening is not possible.

  15. Ferrules seals

    DOEpatents

    Smith, J.L.

    1984-07-10

    A device is provided for sealing an inner tube and an outer tube without excessively deforming the tubes. The device includes two ferrules which cooperate to form a vacuum-tight seal between the inner tube and outer tube and having mating surfaces such that overtightening is not possible. 3 figs.

  16. The effect of a low-frequency sound source (acoustic thermometry of the ocean climate) on the diving behavior of juvenile northern elephant seals, Mirounga angustirostris

    NASA Astrophysics Data System (ADS)

    Costa, Daniel P.; Crocker, Daniel E.; Gedamke, Jason; Webb, Paul M.; Houser, Dorian S.; Blackwell, Susanna B.; Waples, Danielle; Hayes, Sean A.; Le Boeuf, Burney J.

    2003-02-01

    Changes in the diving behavior of individual free-ranging juvenile northern elephant seals, Mirounga angustirostris, exposed to the acoustic thermometry of the ocean climate (ATOC) sound source were examined using data loggers. Data loggers were attached to the animals and measured swim speed, maximum depth of dive, dive duration, surface interval, descent and ascent rate, and descent and ascent angle along with sound pressure level (SPL). The ATOC sound source was at a depth of 939 m and transmitted at 195 dB re: 1 μPa at 1 m centered at 75 Hz with a 37.5-Hz bandwidth. Sound pressure levels (SPL) measured at the seal during transmissions averaged 128 dB and ranged from 118 to 137 dB re: 1 μPa for the 60-90 Hz band, in comparison to ambient levels of 87-107 dB within this band. In no case did an animal end its dive or show any other obvious change in behavior upon exposure to the ATOC sound. Subtle changes in diving behavior were detected, however. During exposure, deviations in descent rate were greater than 1 s.d. of the control mean in 9 of 14 seals. Dive depth increased and descent velocity increased in three animals, ascent velocity decreased in two animals, ascent rate increased in one animal and decreased in another, and dive duration decreased in only one animal. There was a highly significant positive correlation between SPL and descent rate. The biological significance of these subtle changes is likely to be minimal. This is the first study to quantify behavioral responses of an animal underwater with simultaneous measurements of SPL of anthropogenic sounds recorded at the animal.

  17. Fatigue Crack Growth Behavior Evaluation of Grainex Mar-M 247 for NASA's High Temperature, High Speed Turbine Seal Test Rig

    NASA Technical Reports Server (NTRS)

    Delgado, Irebert R.; Steinetz, Bruce M.; Rimnac, Clare M.; Lewandowski, John J.

    2008-01-01

    The fatigue crack growth behavior of Grainex Mar-M 247 is evaluated for NASA s Turbine Seal Test Facility. The facility is used to test air-to-air seals primarily for use in advanced jet engine applications. Because of extreme seal test conditions of temperature, pressure, and surface speeds, surface cracks may develop over time in the disk bolt holes. An inspection interval is developed to preclude catastrophic disk failure by using experimental fatigue crack growth data. By combining current fatigue crack growth results with previous fatigue strain-life experimental work, an inspection interval is determined for the test disk. The fatigue crack growth life of the NASA disk bolt holes is found to be 367 cycles at a crack depth of 0.501 mm using a factor of 2 on life at maximum operating conditions. Combining this result with previous fatigue strain-life experimental work gives a total fatigue life of 1032 cycles at a crack depth of 0.501 mm. Eddy-current inspections are suggested starting at 665 cycles since eddy current detection thresholds are currently at 0.381 mm. Inspection intervals are recommended every 50 cycles when operated at maximum operating conditions.

  18. Seal arrangement

    DOEpatents

    Lundholm, Gunnar

    1987-01-01

    A seal arrangement is provided for preventing gas leakage along a reciprocating piston rod or other reciprocating member passing through a wall which separates a high pressure gas chmber and a low pressure gas chamber. Liquid lubricant is applied to the lower pressure side of a sealing gland surrounding the piston rod to prevent the escape of gas between the rod and the gland. The sealing gland is radially forced against the piston rod by action of a plurality of axially stacked O-rings influenced by an axially acting spring as well as pressure from the gas.

  19. Thermal - Hydraulic Behavior of Unsaturated Bentonite and Sand-Bentonite Material as Seal for Nuclear Waste Repository: Numerical Simulation of Column Experiments

    NASA Astrophysics Data System (ADS)

    Ballarini, E.; Graupner, B.; Bauer, S.

    2015-12-01

    For deep geological repositories of high-level radioactive waste (HLRW), bentonite and sand bentonite mixtures are investigated as buffer materials to form a a sealing layer. This sealing layer surrounds the canisters and experiences an initial drying due to the heat produced by HLRW and a successive re-saturation with fluid from the host rock. These complex thermal, hydraulic and mechanical processes interact and were investigated in laboratory column experiments using MX-80 clay pellets as well as a mixture of 35% sand and 65% bentonite. The aim of this study is to both understand the individual processes taking place in the buffer materials and to identify the key physical parameters that determine the material behavior under heating and hydrating conditions. For this end, detailed and process-oriented numerical modelling was applied to the experiments, simulating heat transport, multiphase flow and mechanical effects from swelling. For both columns, the same set of parameters was assigned to the experimental set-up (i.e. insulation, heater and hydration system), while the parameters of the buffer material were adapted during model calibration. A good fit between model results and data was achieved for temperature, relative humidity, water intake and swelling pressure, thus explaining the material behavior. The key variables identified by the model are the permeability and relative permeability, the water retention curve and the thermal conductivity of the buffer material. The different hydraulic and thermal behavior of the two buffer materials observed in the laboratory observations was well reproduced by the numerical model.

  20. Anaerobic sealing

    SciTech Connect

    Hayre, J.

    1986-05-01

    Anaerobic sealants offer an alternative to conventional methods of joint repair on mains operating at low and medium pressures. The method does not require highly skilled personnel who are diligent in ensuring that the necessary standards of preparation and seal application are achieved. British Gas' experience has shown that lead joints that do not contain yarn or where the yarn has deteriorated are difficult to seal. The evidence so far indicates that yarn is important in ensuring that the low viscosity sealant rapidly wicks around the joint during the injection operation. It is obvious that more research and development is needed in this field, but anaerobic sealing of leaking joints in an effective, innovative method of joint repair.

  1. Advanced bristle seals for gas turbine engines

    NASA Astrophysics Data System (ADS)

    Cabe, Jerry L.

    1993-01-01

    A seven month proof-of-concept program was conducted for an advanced bristle seal, called a bush seal, for use in gas turbine engines. This program was performed as a Small Business Innovation Research (SBIR) Phase 1 project. Bush seal specimen and a full ring bush seal were designed, evaluated, and manufactured for testing. An analytical study of the potential of the bush seal relative to a labyrinth seal was conducted. Static and dynamic testing of the bush seal was performed to determine the behavior of the bristles under pressurization and during contact with a rotating labyrinth tooth. Stable behavior of the bristle elements was observed during static pressurization of a full ring bush seal. The dynamic testing of various configurations of bush seal against a rotating labyrinth tooth showed minimal wear of the bristles relative to a conventional labyrinth seal. The development and application of the bush seal concept to gas turbine engines has the potential of improving the engine's performance while decreasing the degradation of the seal performance over time.

  2. Python fiber optic seal

    SciTech Connect

    Ystesund, K.; Bartberger, J.; Brusseau, C.; Fleming, P.; Insch, K.; Tolk, K.

    1993-08-01

    Sandia National Laboratories has developed a high security fiber optic seal that incorporates tamper resistance features that are not available in commercial fiber optic seals. The Python Seal is a passive fiber optic loop seal designed to give indication of unauthorized entry. The seal includes a fingerprint feature that provides seal identity information in addition to the unique fiber optic pattern created when the seal is installed. The fiber optic cable used for the seal loop is produced with tamper resistant features that increase the difficulty of attacking that component of a seal. A Seal Reader has been developed that will record the seal signature and the fingerprint feature of the seal. A Correlator software program then compares seal images to establish a match or mismatch. SNL is also developing a Polaroid reader to permit hard copies of the seal patterns to be obtained directly from the seal.

  3. GAS SEAL

    DOEpatents

    Monson, H.; Hutter, E.

    1961-07-11

    A seal is described for a cover closing an opening in the top of a pressure vessel that may house a nuclear reactor. The seal comprises a U-shaped trough formed on the pressure vessel around the opening therein, a mass of metal in the trough, and an edge flange on the cover extending loosely into the trough and dipping into the metal mass. The lower portion of the metal mass is kept melted, and the upper portion, solid. The solid pontion of the metal mass prevents pressure surges in the vessel from expelling the liquid portion of the metal mass from the trough; the liquld portion, thus held in place by the solid portion, does not allow gas to go through, and so gas cannot escape through shrinkage holes in the solid portion.

  4. Effects of sonic booms on breeding gray seals and harbor seals on Sable Island, Canada.

    PubMed

    Perry, Elizabeth A; Boness, Daryl J; Insley, Stephen J

    2002-01-01

    The Concorde produces audible sonic booms as it passes 15 km north of Sable Island, Nova Scotia, where gray and harbor seals occur year round. The purpose of this research was to assess how sonic booms affect these seals. The intensity of the booms was measured and three types of data (beach counts, frequency of behavior, and heart rate) were collected before and after booms during the breeding seasons of the two species. In addition to the data taken during breeding, beach counts were made before and after booms during the gray seal moult. The greatest range in overpressure within a single boom was 2.70 psf during gray seal breeding and 2.07 psf during harbor seal breeding. No significant differences were found in the behavior or beach counts of gray seals following sonic booms, regardless of the season. Beach counts and most behaviors of harbor seals also did not differ significantly following booms, however, harbor seals became more vigilant. The heart rates of four gray seal mothers and three pups showed no clear change as a result of booms, but six male harbor seals showed a nonsignificant tendency toward elevated heart rates during the 15-s interval of the boom. These results suggest sonic booms produced by the Concorde, in level flight at altitude and producing on average a sonic boom of 0.9 psf, do not substantially affect the breeding behavior of gray or harbor seals. PMID:11837965

  5. Effects of sonic booms on breeding gray seals and harbor seals on Sable Island, Canada

    NASA Astrophysics Data System (ADS)

    Perry, Elizabeth A.; Boness, Daryl J.; Insley, Stephen J.

    2002-01-01

    The Concorde produces audible sonic booms as it passes 15 km north of Sable Island, Nova Scotia, where gray and harbor seals occur year round. The purpose of this research was to assess how sonic booms affect these seals. The intensity of the booms was measured and three types of data (beach counts, frequency of behavior, and heart rate) were collected before and after booms during the breeding seasons of the two species. In addition to the data taken during breeding, beach counts were made before and after booms during the gray seal moult. The greatest range in overpressure within a single boom was 2.70 psf during gray seal breeding and 2.07 psf during harbor seal breeding. No significant differences were found in the behavior or beach counts of gray seals following sonic booms, regardless of the season. Beach counts and most behaviors of harbor seals also did not differ significantly following booms, however, harbor seals became more vigilant. The heart rates of four gray seal mothers and three pups showed no clear change as a result of booms, but six male harbor seals showed a nonsignificant tendency toward elevated heart rates during the 15-s interval of the boom. These results suggest sonic booms produced by the Concorde, in level flight at altitude and producing on average a sonic boom of 0.9 psf, do not substantially affect the breeding behavior of gray or harbor seals.

  6. Variable friction secondary seal for face seals

    NASA Technical Reports Server (NTRS)

    Dirusso, E. (Inventor)

    1986-01-01

    Vibration and stability of a primary seal ring is controlled by a secondary seal system. An inflatable bladder which forms a portion of the secondary seal varies the damping applied to this seal ring. The amplitude of vibration of the primary seal ring is sensed with a proximity probe that is connected to a microprocessor in a control system. The bladder pressure is changed by the control system to mitigate any sensed instability or vibration.

  7. Fluid pressure balanced seal

    NASA Technical Reports Server (NTRS)

    Marsh, H. W. (Inventor)

    1966-01-01

    A seal which increases in effectiveness with increasing pressure is presented. The seal's functional capability throughout both static and dynamic operation makes it particularly useful for sealing ball valve ports. Other features of the seal include the ability to seal two opposed surfaces simultaneously, tolerance of small misalignments, tolerance of wide temperature ranges, ability to maintain positive sealing contact under conditions of internal or external pressurization, and ability to conform to slight irregularities in seal or surface contours.

  8. The dynamics of grey seals ( Halichoerus grypus) off Amrum in the south-eastern North Sea — evidence of an open population

    NASA Astrophysics Data System (ADS)

    Abt, Kai F.; Hoyer, Nils; Koch, Lothar; Adelung, Dieter

    2002-02-01

    Grey seals ( Halichoerus grypus) have been extinct in the south-eastern North Sea for centuries. Only in recent decades have they re-established a few colonies, the first of which was located on a group of sand bars off the German island of Amrum. Based on frequent counts from aircraft and boats in 1976-2000, and a photo-identification program in 1997, we investigated seasonal dynamics, trends in abundance, pup production, and pup survival in this population. Numbers of hauled-out seals were highest in spring, with a peak of 70-100 in late March or early April, and usually lower than 40 from late May to late January, including the winter breeding season. Both spring and summer counts indicated an average increase of 4-5% per year. Annual pup production was 3-10 in 1988-1995 and 9-13 in 1996-1999, suggesting a breeding stock of only about half the minimum total population size, i.e. 137 individually recognised seals in 1997. The estimated survival of pups until weaning seemed high enough to support autochthonous increase, and hence suggested a self-sustaining breeding stock at least until the late 1990s. Pup survival declined, however, from 95-100% in 1988-1991 to 60-70% in 1992-1999, probably due to erosion of the sand bars. From (i) the relative excess of hauled-out seals in spring, as compared to the phenology of stocks in the western North Sea, (ii) turnover and net loss of individuals during the spring and summer of 1997, as indicated by photo-ID records, and (iii) the low apparent per capita birth rate, we suggest that grey seals off Amrum split into a resident breeding stock and a similar or higher number of seals immigrating outside the breeding season. The latter may originate from larger colonies in the southern and western North Sea, and return there for breeding. In the future, grey seals currently breeding off Amrum may eventually leave the area because of deteriorating conditions. However, a decline of numbers occurring in spring and summer would not

  9. Dynamic Face Seal Arrangement

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher (Inventor)

    1999-01-01

    A radial face seal arrangement is disclosed comprising a stationary seal ring that is spring loaded against a seal seat affixed to a rotating shaft. The radial face seal arrangement further comprises an arrangement that not only allows for preloading of the stationary seal ring relative to the seal seat, but also provides for dampening yielding a dynamic seating response for the radial face seal arrangement. The overall seal system, especially regarding the selection of the material for the stationary seal ring, is designed to operate over a wide temperature range from below ambient up to 900 C.

  10. Regenerator seal design

    DOEpatents

    Eckart, Francis H.

    1982-01-01

    A rotary regenerator disc matrix has a face seal with a cross arm and arcuate rim segments joined by prestress clamps to prestrain the arcuate rim seals so as to compensate seal rim twisting or coning and resultant disc face seal leakage as produced by operating thermal gradients across the seal.

  11. Sealing Mechanical Cryogenic Coolers

    NASA Technical Reports Server (NTRS)

    Richter, R.

    1985-01-01

    Metal bellows used to seal Vuilleumier and Stirling-cycle cryogenic coolers, replacing sliding seals that failed after only 3,000 hours of service. Metal bellows, incorporated in displacer design provide nonrubbing dynamic seal. Lifetime of cryogenic cooler no longer limited by loss of sealing material and by deterioration of regenerators due to clogging by seal debris.

  12. Regenerator seal

    NASA Technical Reports Server (NTRS)

    Davis, Leonard C. (Inventor); Pacala, Theodore (Inventor); Sippel, George R. (Inventor)

    1981-01-01

    A method for manufacturing a hot side regenerator cross arm seal assembly having a thermally stablilized wear coating with a substantially flat wear surface thereon to seal between low pressure and high pressure passages to and from the hot inboard side of a rotary regenerator matrix includes the steps of forming a flat cross arm substrate member of high nickel alloy steel; fixedly securing the side edges of the substrate member to a holding fixture with a concave surface thereacross to maintain the substrate member to a slightly bent configuration on the fixture surface between the opposite ends of the substrate member to produce prestress therein; applying coating layers on the substrate member including a wear coating of plasma sprayed nickel oxide/calcium flouride material to define a wear surface of slightly concave form across the restrained substrate member between the free ends thereon; and thereafter subjecting the substrate member and the coating thereon to a heat treatment of 1600.degree. F. for sixteen hours to produce heat stabilizing growth in the coating layers on the substrate member and to produce a thermally induced growth stress in the wear surface that substantially equalizes the prestress in the substrate whereby when the cross arm is removed from the fixture surface following the heat treatment step a wear face is formed on the cross arm assembly that will be substantially flat between the ends.

  13. Triple acting radial seal

    DOEpatents

    Ebert, Todd A; Carella, John A

    2012-03-13

    A triple acting radial seal used as an interstage seal assembly in a gas turbine engine, where the seal assembly includes an interstage seal support extending from a stationary inner shroud of a vane ring, the interstage seal support includes a larger annular radial inward facing groove in which an outer annular floating seal assembly is secured for radial displacement, and the outer annular floating seal assembly includes a smaller annular radial inward facing groove in which an inner annular floating seal assembly is secured also for radial displacement. A compliant seal is secured to the inner annular floating seal assembly. The outer annular floating seal assembly encapsulates the inner annular floating seal assembly which is made from a very low alpha material in order to reduce thermal stress.

  14. Fundamentals of fluid sealing

    NASA Technical Reports Server (NTRS)

    Zuk, J.

    1976-01-01

    The fundamentals of fluid sealing, including seal operating regimes, are discussed and the general fluid-flow equations for fluid sealing are developed. Seal performance parameters such as leakage and power loss are presented. Included in the discussion are the effects of geometry, surface deformations, rotation, and both laminar and turbulent flows. The concept of pressure balancing is presented, as are differences between liquid and gas sealing. Mechanisms of seal surface separation, fundamental friction and wear concepts applicable to seals, seal materials, and pressure-velocity (PV) criteria are discussed.

  15. Increased Contracaecum osculatum infection in Baltic cod (Gadus morhua) livers (1982-2012) associated with increasing grey seal (Halichoerus gryphus) populations.

    PubMed

    Haarder, Simon; Kania, Per W; Galatius, Anders; Buchmann, Kurt

    2014-07-01

    Grey seals (Halichoerus gryphus), the main final host of the gastric parasitic nematode Contracaecum osculatum in the Baltic, have recently recolonized the southwestern Baltic Sea. This colonization could lead to an increase in prevalence and intensity of third-stage larvae of C. osculatum in livers of Baltic cod (Gadus morhua), which serve as transport host for this helminth. We performed a parasitologic study of cod in spring 2012 and compared the results with previously unpublished data from 1982/1983. Additionally, grey seals were counted annually from 2000 to 2011 at three haul-out sites in the southwestern Baltic. Of 97 cod livers examined in the 1982/1983 survey, 22% harbored C. osculatum larvae, whereas 55.1% of the examined cod livers (n=185) were infected in 2012; the mean intensity and mean abundance increased from 4.3 and 0.9 to 20.2 and 11.1, respectively. Molecular identification (PCR) confirmed the identity of the larvae. The grey seal population increased markedly during the 12-yr period. We suggest that the elevated parasitism of cod livers is associated with the successful re-establishment of grey seals in the southwestern Baltic. PMID:24779467

  16. Turbine disc sealing assembly

    DOEpatents

    Diakunchak, Ihor S.

    2013-03-05

    A disc seal assembly for use in a turbine engine. The disc seal assembly includes a plurality of outwardly extending sealing flange members that define a plurality of fluid pockets. The sealing flange members define a labyrinth flow path therebetween to limit leakage between a hot gas path and a disc cavity in the turbine engine.

  17. Indium sealing techniques.

    NASA Technical Reports Server (NTRS)

    Hochuli, U.; Haldemann, P.

    1972-01-01

    Gold films are used as an alloying flux to form 5-micron-thick indium film seals at temperatures below 300 C. Pyrex was sealed to quartz, ULE, CER-VIT, Irtran 2, Ge, GaAs, Invar, Kovar, Al, and Cu. The seals can also be used as current feedthroughs and graded seals.

  18. Sealing packer

    SciTech Connect

    Clifton, T.G.; Brookey, R.L.

    1987-02-03

    A sealing packer is described for a well casing characterized by: a tubular inner sleeve with a passage therethrough; an upper outer sleeve assembly mounted about the inner sleeve and including: a resiliently deformable upper packing element; seat means for seating the upper packing element; hold down means for engaging a well casing and retaining the outer sleeve assembly stationary against upwardly directed well pressures; a lower outer sleeve assembly slidably mounted about the inner sleeve and including: a resiliently deformable lower packing element; first seat means for seating the lower packing element; abutment means for compressing the upper packing element between the abutment means and the seat of the upper outer sleeve assembly; the upper packing element constructed such that when compressed it engages the well casing, setting means for fixing a second seat means of the lower outer sleeve assembly relative to the well casing: the lower packing element being deformable between the first and second seat means of the lower outer sleeve assembly to engage the well casing; and piston means normally adjacent the abutment means and separable therefrom, the piston means responsive to fluid pressure in the passage and in the well casing between the lower and upper packing elements when the packing elements deformably engage the well casing to separate from the abutment means and further deform the upper packing element.

  19. Mechanical seal assembly

    DOEpatents

    Kotlyar, Oleg M.

    2002-01-01

    An improved mechanical seal assembly is provided for sealing rotating shafts with respect to their shaft housings, wherein the rotating shafts are subject to substantial axial vibrations. The mechanical seal assembly generally includes a rotating sealing ring fixed to the shaft, a non-rotating sealing ring adjacent to and in close contact with the rotating sealing ring for forming an annular seal about the shaft, and a mechanical diode element that applies a biasing force to the non-rotating sealing ring by means of hemispherical joint. The alignment of the mechanical diode with respect to the sealing rings is maintained by a series of linear bearings positioned axially along a desired length of the mechanical diode. Alternative embodiments include mechanical or hydraulic amplification components for amplifying axial displacement of the non-rotating sealing ring and transfering it to the mechanical diode.

  20. Turbine blade platform seal

    DOEpatents

    Zagar, Thomas W.; Schiavo, Anthony L.

    2001-01-01

    A rotating blade group 90 for a turbo-machine having an improved device for sealing the gap 110 between the edges 112,114 of adjacent blade platforms 96,104. The gap 110 between adjacent blades 92,100 is sealed by a seal pin 20 its central portion 110 and by a seal plate 58,60 at each of the front 54 and rear 56 portions. The seal plates 58,60 are inserted into corresponding grooves 62,64 formed in the adjacent edges 112,114 of adjoining blades 92,100 and held in place by end plates 40,42. The end of the seal plates 58,60 may be chamfered 78,80 to improve the seal against the end plate 40,42. The seal pin 20 provides the required damping between the blades 92,100 and the seal plates 58,60 provide improved sealing effectiveness.

  1. Mechanical seal assembly

    DOEpatents

    Kotlyar, Oleg M.

    2001-01-01

    An improved mechanical seal assembly is provided for sealing rotating shafts with respect to their shaft housings, wherein the rotating shafts are subject to substantial axial vibrations. The mechanical seal assembly generally includes a rotating sealing ring fixed to the shaft, a non-rotating sealing ring adjacent to and in close contact with the rotating sealing ring for forming an annular seal about the shaft, and a mechanical diode element that applies a biasing force to the non-rotating sealing ring by means of hemispherical joint. The alignment of the mechanical diode with respect to the sealing rings is maintained by a series of linear bearings positioned axially along a desired length of the mechanical diode. Alternative embodiments include mechanical or hydraulic amplification components for amplifying axial displacement of the non-rotating sealing ring and transferring it to the mechanical diode.

  2. Seal design alternatives study

    SciTech Connect

    Van Sambeek, L.L.

    1993-06-01

    This report presents the results from a study of various sealing alternatives for the WIPP sealing system. Overall, the sealing system has the purpose of reducing to the extent possible the potential for fluids (either gas or liquid) from entering or leaving the repository. The sealing system is divided into three subsystems: drift and panel seals within the repository horizon, shaft seals in each of the four shafts, and borehole seals. Alternatives to the baseline configuration for the WIPP seal system design included evaluating different geometries and schedules for seal component installations and the use of different materials for seal components. Order-of-magnitude costs for the various alternatives were prepared as part of the study. Firm recommendations are not presented, but the advantages and disadvantages of the alternatives are discussed. Technical information deficiencies are identified and studies are outlined which can provide required information.

  3. Flexible sliding seal

    NASA Technical Reports Server (NTRS)

    Wallenhorst, E. L.

    1980-01-01

    Circular seal both slides and flexes to accomodate relative motion between two sealed members. Originally developed for Space Shuttle orbiter, it contains sliding seal to accommodate engine gimbaling and flexible seal that absorbs forward motion at high thrust of engine heat shield relative to airframe. Other possible applications are in support structures of heavy machinery and vehicle engines. Flexible sliding seal is ring about 7 feet in diameter and can withstand temperatures up to 1,600 F.

  4. Scaling matters: incorporating body composition into Weddell seal seasonal oxygen store comparisons reveals maintenance of aerobic capacities.

    PubMed

    Shero, Michelle R; Costa, Daniel P; Burns, Jennifer M

    2015-10-01

    Adult Weddell seals (Leptonychotes weddellii) haul-out on the ice in October/November (austral spring) for the breeding season and reduce foraging activities for ~4 months until their molt in the austral fall (January/February). After these periods, animals are at their leanest and resume actively foraging for the austral winter. In mammals, decreased exercise and hypoxia exposure typically lead to decreased production of O2-carrying proteins and muscle wasting, while endurance training increases aerobic potential. To test whether similar effects were present in marine mammals, this study compared the physiology of 53 post-molt female Weddell seals in the austral fall to 47 pre-breeding females during the spring in McMurdo Sound, Antarctica. Once body mass and condition (lipid) were controlled for, there were no seasonal changes in total body oxygen (TBO2) stores. Within each season, hematocrit and hemoglobin values were negatively correlated with animal size, and larger animals had lower mass-specific TBO2 stores. But because larger seals had lower mass-specific metabolic rates, their calculated aerobic dive limit was similar to smaller seals. Indicators of muscular efficiency, myosin heavy chain composition, myoglobin concentrations, and aerobic enzyme activities (citrate synthase and β-hydroxyacyl CoA dehydrogenase) were likewise maintained across the year. The preservation of aerobic capacity is likely critical to foraging capabilities, so that following the molt Weddell seals can rapidly regain body mass at the start of winter foraging. In contrast, muscle lactate dehydrogenase activity, a marker of anaerobic metabolism, exhibited seasonal plasticity in this diving top predator and was lowest after the summer period of reduced activity. PMID:26164426

  5. Rotary shaft sealing assembly

    DOEpatents

    Dietle, Lannie L.; Schroeder, John E.; Kalsi, Manmohan S.; Alvarez, Patricio D.

    2010-09-21

    A rotary shaft sealing assembly in which a first fluid is partitioned from a second fluid in a housing assembly having a rotary shaft located at least partially within. In one embodiment a lip seal is lubricated and flushed with a pressure-generating seal ring preferably having an angled diverting feature. The pressure-generating seal ring and a hydrodynamic seal may be used to define a lubricant-filled region with each of the seals having hydrodynamic inlets facing the lubricant-filled region. Another aspect of the sealing assembly is having a seal to contain pressurized lubricant while withstanding high rotary speeds. Another rotary shaft sealing assembly embodiment includes a lubricant supply providing a lubricant at an elevated pressure to a region between a lip seal and a hydrodynamic seal with a flow control regulating the flow of lubricant past the lip seal. The hydrodynamic seal may include an energizer element having a modulus of elasticity greater than the modulus of elasticity of a sealing lip of the hydrodynamic seal.

  6. Rotary shaft sealing assembly

    DOEpatents

    Dietle, Lannie L; Schroeder, John E; Kalsi, Manmohan S; Alvarez, Patricio D

    2013-08-13

    A rotary shaft sealing assembly in which a first fluid is partitioned from a second fluid in a housing assembly having a rotary shaft located at least partially within. In one embodiment a lip seal is lubricated and flushed with a pressure-generating seal ring preferably having an angled diverting feature. The pressure-generating seal ring and a hydrodynamic seal may be used to define a lubricant-filled region with each of the seals having hydrodynamic inlets facing the lubricant-filled region. Another aspect of the sealing assembly is having a seal to contain pressurized lubricant while withstanding high rotary speeds. Another rotary shaft sealing assembly embodiment includes a lubricant supply providing a lubricant at an elevated pressure to a region between a lip seal and a hydrodynamic seal with a flow control regulating the flow of lubricant past the lip seal. The hydrodynamic seal may include an energizer element having a modulus of elasticity greater than the modulus of elasticity of a sealing lip of the hydrodynamic seal.

  7. The modified Cobra Seal

    SciTech Connect

    Ystesund, K.J.; Drayer, D.D.

    1990-01-01

    The Cobra Seal was developed in response to the International Atomic Energy Agency's request for an in situ verifiable seal. The Type E metal cap seal, still widely used by the IAEA, must be removed and returned to Agency headquarters for verification. The Cobra Seal allows an inspector to verify seal identity and integrity on site, without removing the seal. The seal consists of a loop of multi-strand fiber optic cable, which can be routed around or through the object to be sealed, and a seal body that secures the ends of the fiber optic cable. A cutting blade in the seal body randomly cuts a portion of the optical fibers in the cable. After the seal assembly is completed, a reference image is recorded of the unique pattern of light spots produced when the seal face is illuminated. Subsequent photographs of the seal pattern are compared to the original to establish the seal identity and integrity. This paper reviews the improvements and the technology of the cobra seal system. 3 refs., 5 figs.

  8. Overview of NASA Glenn Seal Developments

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M.; Proctor, Margaret P.; Dunlap, Patrick H., Jr.; Delgado, Irebert; DeMange, Jeffrey J.; Daniels, Christopher C.; Lattime, Scott B.

    2004-01-01

    Turbine engine studies have shown that reducing high pressure turbine (HPT) blade tip clearances will reduce fuel burn, lower emissions, retain exhaust gas temperature margin and increase range. Dr. Lattime presented the design and development status of a new Active Clearance Control Test rig aimed at demonstrating advanced ACC approaches and sensors. Mr. Melcher presented controls considerations for turbine active clearance control. Mr. Geisheimer of Radatech presented an overview of their microwave blade tip sensor technology. Microwave tip sensors show promise of operation in the extreme gas temperatures present in the HPT location. Mr. Justak presented an overview of non-contacting seal developments at Advanced Technologies Group. Dr. Braun presented investigations into a non-contacting finger seal under development by NASA GRC and University of Akron. Dr. Stango presented analytical assessments of the effects of flow-induced radial loads on brush seal behavior. Mr. Flaherty presented innovative seal and seal fabrication developments at FlowServ. Mr. Chappel presented abradable seal developments at Technetics. Dr. Daniels presented an overview of NASA GRC s acoustic seal developments. NASA is investigating the ability to harness high amplitude acoustic waves, possible through a new field of acoustics called Resonant Macrosonic Synthesis, to effect a non-contacting, low leakage seal. Dr. Daniels presented early results showing the ability to restrict flow via acoustic pressures. Dr. Athavale presented numerical results simulating the flow blocking capability of a pre-prototype acoustic seal.

  9. Nuclear reactor sealing system

    DOEpatents

    McEdwards, James A.

    1983-01-01

    A liquid metal-cooled nuclear reactor sealing system. The nuclear reactor includes a vessel sealed at its upper end by a closure head. The closure head comprises at least two components, one of which is rotatable; and the two components define an annulus therebetween. The sealing system includes at least a first and second inflatable seal disposed in series in an upper portion of the annulus. The system further includes a dip seal extending into a body of insulation located adjacent a bottom portion of the closure head. The dip seal comprises a trough formed by a lower portion of one of the components, and a seal blade pendently supported from the other component and extending downwardly into the trough. A body of liquid metal is contained in the trough which submerges a portion of the seal blade. The seal blade is provided with at least one aperture located above the body of liquid metal for providing fluid communication between the annulus intermediate the dip seal and the inflatable seals, and a body of cover gas located inside the vessel. There also is provided means for introducing a purge gas into the annulus intermediate the inflatable seals and the seal blade. The purge gas is introduced in an amount sufficient to substantially reduce diffusion of radioactive cover gas or sodium vapor up to the inflatable seals. The purge gas mixes with the cover gas in the reactor vessel where it can be withdrawn from the vessel for treatment and recycle to the vessel.

  10. Inboard seal mounting

    DOEpatents

    Hayes, John R.

    1983-01-01

    A regenerator assembly for a gas turbine engine has a hot side seal assembly formed in part by a cast metal engine block having a seal recess formed therein that is configured to supportingly receive ceramic support blocks including an inboard face thereon having a regenerator seal face bonded thereto. A pressurized leaf seal is interposed between the ceramic support block and the cast metal engine block to bias the seal wear face into sealing engagement with a hot side surface of a rotary regenerator matrix.

  11. Compliant Foil Seal Investigations

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret; Delgado, Irebert

    2004-01-01

    Room temperature testing of an 8.5 inch diameter foil seal was conducted in the High Speed, High Temperature Turbine Seal Test Rig at the NASA Glenn Research Center. The seal was operated at speeds up to 30,000 rpm and pressure differentials up to 75 psid. Seal leakage and power loss data will be presented and compared to brush seal performance. The failure of the seal and rotor coating at 30,000 rpm and 15 psid will be presented and future development needs discussed.

  12. Bentonite as a waste isolation pilot plant shaft sealing material

    SciTech Connect

    Daemen, J.; Ran, Chongwei

    1996-12-01

    Current designs of the shaft sealing system for the Waste Isolation Pilot Plant (WIPP) propose using bentonite as a primary sealing component. The shaft sealing designs anticipate that compacted bentonite sealing components can perform through the 10,000-year regulatory period and beyond. To evaluate the acceptability of bentonite as a sealing material for the WIPP, this report identifies references that deal with the properties and characteristics of bentonite that may affect its behavior in the WIPP environment. This report reviews published studies that discuss using bentonite as sealing material for nuclear waste disposal, environmental restoration, toxic and chemical waste disposal, landfill liners, and applications in the petroleum industry. This report identifies the physical and chemical properties, stability and seal construction technologies of bentonite seals in shafts, especially in a saline brine environment. This report focuses on permeability, swelling pressure, strength, stiffness, longevity, and densification properties of bentonites.

  13. Seal Out Tooth Decay

    MedlinePlus

    ... Topics > Tooth Decay (Caries) > Seal Out Tooth Decay Seal Out Tooth Decay Main Content What are dental ... back teeth decay so easily? Who should get seal​ants? Should sealants be put on baby teeth? ...

  14. Magnetically Actuated Seal

    NASA Technical Reports Server (NTRS)

    Pinera, Alex

    2013-01-01

    This invention is a magnetically actuated seal in which either a single electromagnet, or multiple electromagnets, are used to control the seal's position. This system can either be an open/ close type of system or an actively controlled system.

  15. Energy efficient face seal

    NASA Technical Reports Server (NTRS)

    Sehnal, J.; Sedy, J.; Etsion, I.; Zobens, A.

    1982-01-01

    Torque, face temperature, leakage, and wear of a flat face seal were compared with three coned face seals at pressures up to 2758 kPa and speeds up to 8000 rpm. Axial movement of the mating seal parts was recorded by a digital data acquisition system. The coning of the tungsten carbide primary ring ranged from .51 micro-m to 5.6 micro-m. The torque of the coned face seal balanced to 76.3% was an average 42% lower, the leakage eleven times higher, than that of the standard flat face seal. The reduction of the balance of the coned face seal to 51.3% resulted by decreasing the torque by an additional 44% and increasing leakage 12 to 230 times, depending on the seal shaft speed. No measurable wear was observed on the face of the coned seals.

  16. Titanium sealing glasses and seals formed therefrom

    DOEpatents

    Brow, Richard K.; McCollister, Howard L.; Phifer, Carol C.; Day, Delbert E.

    1997-01-01

    Alkaline-earth lanthanoborate sealing-glass compositions containing CaO, La.sub.2 O.sub.3, B.sub.2 O.sub.3, TiO.sub.2 and Al.sub.2 O.sub.3 in various combinations of mole-% are provided. These sealing-glass compositions are useful for forming hermetic glass-to-metal seals with titanium and titanium alloys that have a high aqueous durability for component or device applications requiring exposure to moisture, water or body fluids. Particular applications of the titanium sealing-glass compositions include forming glass-to-metal seals for lithium batteries and implanted biomedical devices (e.g. batteries, pacemakers, defibrillators, pumps).

  17. Titanium sealing glasses and seals formed therefrom

    DOEpatents

    Brow, R.K.; McCollister, H.L.; Phifer, C.C.; Day, D.E.

    1997-12-02

    Alkaline-earth lanthanoborate sealing-glass compositions containing CaO, La{sub 2}O{sub 3}, B{sub 2}O{sub 3}, TiO{sub 2} and Al{sub 2}O{sub 3} in various combinations of mole-% are provided. These sealing-glass compositions are useful for forming hermetic glass-to-metal seals with titanium and titanium alloys that have a high aqueous durability for component or device applications requiring exposure to moisture, water or body fluids. Particular applications of the titanium sealing-glass compositions include forming glass-to-metal seals for lithium batteries and implanted biomedical devices (e.g. batteries, pacemakers, defibrillators, pumps). 2 figs.

  18. Stability and bifurcation analysis of rotor-bearing-seal system

    NASA Astrophysics Data System (ADS)

    Ying, G. Y.; Liu, S. L.; Ma, R.; Zheng, S. Y.

    2016-05-01

    Labyrinth seals were extensively used in turbine units, and the seal fluid forces may induce self-excited vibrations of rotor under certain conditions. It has become the main factor to instability of rotor system. In this paper Muszynska seal fluid force model is used to investigate the stability of the rotor system. Nonlinear equations are numerically solved by Newmark integration method. The effect of different seal clearances and differential pressures on system stability is studied. The calculation results show that the dominant vibration component leading to instability changes with different seal clearance. With the differential pressure increased, the unstable speed is reduced. Then the bifurcation behavior of the system with and without seal force is calculated. Results show that the rotor vibration becomes severe and complicated, and the bifurcation behavior of the system has been changed when seal force is considered.

  19. Damping seals for turbomachinery

    NASA Technical Reports Server (NTRS)

    Vonpragenau, G. L.

    1982-01-01

    A rotor seal is proposed that restricts leakage like a labyrinth seal, but extends the stabilizing speed range beyond twice the first critical speed. The dynamic parameters were derived from bulk flow equations without requiring a dominant axial flow. The flow is considered incompressible and turbulent. Damping seals are shown to be feasible for extending the speed range of high performance turbomachinery beyond the limit imposed by conventional seals.

  20. Tamper-indicating seal

    DOEpatents

    Fiarman, Sidney; Degen, Michael F.; Peters, Henry F.

    1985-01-01

    There is disclosed a tamper-indicating seal that permits in the field inspection and detection of tampering. Said seal comprises a shrinkable tube having a visible pattern of markings which is shrunk over the item to be sealed, and a second transparent tube, having a second visible marking pattern, which is shrunk over the item and the first tube. The relationship between the first and second set of markings produces a pattern so that the seal may not be removed without detection.

  1. Resilient Braided Rope Seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor); Kren, Lawrence A. (Inventor)

    1996-01-01

    A resilient braided rope seal for use in high temperature applications. The resilient braided rope seal includes a center core of fibers, a resilient 5 member overbraided by at least one layer of braided sheath fibers tightly packed together. The resilient member adds significant stiffness to the seal while maintaining resiliency. Furthermore, the seal permanent set and hysteresis are greatly reduced. Finally, improved load capabilities are provided.

  2. Turbomachine Interface Sealing

    NASA Technical Reports Server (NTRS)

    Hendricks, Robert C.; Chupp, Raymond E.; Lattime, Scott B.; Steinetz, Bruce M.

    2005-01-01

    Sealing interfaces and coatings, like lubricants, are sacrificial, giving up their integrity for the benefit of the component. Clearance control is a major issue in power systems turbomachine design and operational life. Sealing becomes the most cost-effective way to enhance system performance. Coatings, films, and combined use of both metals and ceramics play a major role in maintaining interface clearances in turbomachine sealing and component life. This paper focuses on conventional and innovative materials and design practices for sealing interfaces.

  3. Hermetically Sealed Compressor

    NASA Technical Reports Server (NTRS)

    Holtzapple, Mark T.

    1994-01-01

    Proposed hermetically sealed pump compresses fluid to pressure up to 4,000 atm (400 MPa). Pump employs linear electric motor instead of rotary motor to avoid need for leakage-prone rotary seals. In addition, linear-motor-powered pump would not require packings to seal its piston. Concept thus eliminates major cause of friction and wear. Pump is double-ended diaphragm-type compressor. All moving parts sealed within compressor housing.

  4. Security seal. [Patent application

    DOEpatents

    Gobeli, G.W.

    1981-11-17

    Security for a package or verifying seal in plastic material is provided by a print seal with unique thermally produced imprints in the plastic. If tampering is attempted, the material is irreparably damaged and thus detectable. The pattern of the imprints, similar to fingerprints are recorded as a positive identification for the seal, and corresponding recordings made to allow comparison. The integrity of the seal is proved by the comparison of imprint identification records made by laser beam projection.

  5. Seals development and evaluation

    SciTech Connect

    Waddoups, I.G.; Horton, P.R.V.

    1994-08-01

    This paper discusses Sandia`s support of DOE`s domestic seals program. Testing was conducted on several pressure sensitive seals and a few wire loop seals currently in use as well as on a few new seals. The testing on new seals concentrated on loop seals and included two fiber optic seals and a recently available wire loop seal being considered for use. Environmental, handling and vulnerability testing were conducted. The standardized testing approach used and the results of the testing are summarized. The status of evaluations for using higher security active and passive seals for domestic applications is also presented. The conclusion of the testing -of seals currently in use is that, even though there is some variability in their ability to meet all the test criterion, they are all generally acceptable by the test standards used. The motivation for evaluating higher security seals is to ascertain if seals could be used in broader domestic environment and result in improved cost-effectiveness.

  6. Skew resisting hydrodynamic seal

    DOEpatents

    Conroy, William T.; Dietle, Lannie L.; Gobeli, Jeffrey D.; Kalsi, Manmohan S.

    2001-01-01

    A novel hydrodynamically lubricated compression type rotary seal that is suitable for lubricant retention and environmental exclusion. Particularly, the seal geometry ensures constraint of a hydrodynamic seal in a manner preventing skew-induced wear and provides adequate room within the seal gland to accommodate thermal expansion. The seal accommodates large as-manufactured variations in the coefficient of thermal expansion of the sealing material, provides a relatively stiff integral spring effect to minimize pressure-induced shuttling of the seal within the gland, and also maintains interfacial contact pressure within the dynamic sealing interface in an optimum range for efficient hydrodynamic lubrication and environment exclusion. The seal geometry also provides for complete support about the circumference of the seal to receive environmental pressure, as compared the interrupted character of seal support set forth in U.S. Pat. Nos. 5,873,576 and 6,036,192 and provides a hydrodynamic seal which is suitable for use with non-Newtonian lubricants.

  7. Collapsable seal member

    SciTech Connect

    Sherrell, Dennis L.

    1990-01-01

    A hollow, collapsable seal member normally disposed in a natural expanded state offering fail-safe pressure sealing against a seating surface and adapted to be evacuated by a vacuum force for collapsing the seal member to disengage the same from said seating surface.

  8. Collapsable seal member

    SciTech Connect

    Sherrell, D.L.

    1983-12-08

    A hollow, collapsable seal member normally disposed in a natural expanded state offering fail-safe pressure sealing against a seating surface and adapted to be evacuated by a vacuum force for collapsing the seal member to disengage the same from said seating surface.

  9. Circumferential shaft seal

    NASA Technical Reports Server (NTRS)

    Ludwig, L. P. (Inventor)

    1980-01-01

    A circumferential shaft seal is described which comprises two sealing rings held to a rotating shaft by means of a surrounding elastomeric band. The rings are segmented and are of a rigid sealing material such as carbon or a polyimide and graphite fiber composite.

  10. Rough/Smooth Rotary Seal

    NASA Technical Reports Server (NTRS)

    Chen, W. C.; Jackson, E. D.

    1986-01-01

    Rotary seal for turbopump combines low leakage of labyrinth seal with high load capacity of smooth-surface annular seal. New seal acts as strong journal bearing that provides high stiffness - about same as that of ball bearings for turbopump shaft. Seal shares load with ball bearings and prolongs their lives. At same time, seal allows minimal leakage of fluid from pump. By combining leakage control and bearing functions, seal makes multiple seals unnecessary and allows compact design.

  11. SEAL FOR ROTATING SHAFT

    DOEpatents

    Coffman, R.T.

    1957-12-10

    A seal is described for a rotatable shaft that must highly effective when the shaft is not rotating but may be less effective while the shaft is rotating. Weights distributed about a sealing disk secured to the shaft press the sealing disk against a tubular section into which the shiilt extends, and whem the shaft rotates, the centrifugal forces on the weights relieve the pressurc of the sealing disk against the tubular section. This action has the very desirible result of minimizing the wear of the rotating disk due to contact with the tubular section, while affording maximum sealing action when it is needed.

  12. Tamper-indicating seal

    DOEpatents

    Fiarman, S.; Degen, M.F.; Peters, H.F.

    1982-08-13

    There is disclosed a tamper-indicating seal that permits in the field inspection and detection of tampering. Said seal comprises a shrinkable tube having a visible pattern of markings which is shrunk over th item to be sealed, and a second transparent tube, having a second visible marking pattern, which is shrunk over the item and the first tube. The relationship between the first and second set of markings produces a pattern so that the seal may not be removed without detection. The seal is particularly applicable to UF/sub 6/ cylinder valves.

  13. Low Cost, Durable Seal

    SciTech Connect

    Roberts, George; Parsons, Jason; Friedman, Jake

    2010-12-17

    Seal durability is critical to achieving the 2010 DOE operational life goals for both stationary and transportation PEM fuel cell stacks. The seal material must be chemically and mechanically stable in an environment consisting of aggressive operating temperatures, humidified gases, and acidic membranes. The seal must also be producible at low cost. Currentlyused seal materials do not meet all these requirements. This project developed and demonstrated a high consistency hydrocarbon rubber seal material that was able to meet the DOE technical and cost targets. Significant emphasis was placed on characterization of the material and full scale molding demonstrations.

  14. Air Force Seal Programs

    NASA Technical Reports Server (NTRS)

    Mayhew, Ellen R.

    1996-01-01

    Seal technology development is an important part of the Air Force's participation in the Integrated High Performance Turbine Engine Technology (IHPTET) initiative, the joint DOD, NASA, ARPA, and industry endeavor to double turbine engine capabilities by the turn of the century. Significant performance and efficiency improvements can be obtained through reducing internal flow system leakage, but seal environment requirements continue to become more extreme as the engine thermodynamic cycles advance towards these IHPTET goals. Seal technology continues to be pursued by the Air Force to control leakage at the required conditions. This presentation briefly describes current seal research and development programs and gives a summary of seal applications in demonstrator and developmental engines.

  15. Fuel cell manifold sealing system

    DOEpatents

    Grevstad, Paul E.; Johnson, Carl K.; Mientek, Anthony P.

    1980-01-01

    A manifold-to-stack seal and sealing method for fuel cell stacks. This seal system solves the problem of maintaining a low leak rate manifold seal as the fuel cell stack undergoes compressive creep. The seal system eliminates the problem of the manifold-to-stack seal sliding against the rough stack surface as the stack becomes shorter because of cell creep, which relative motion destroys the seal. The seal system described herein utilizes a polymer seal frame firmly clamped between the manifold and the stack such that the seal frame moves with the stack. Thus, as the stack creeps, the seal frame creeps with it, and there is no sliding at the rough, tough to seal, stack-to-seal frame interface. Here the sliding is on a smooth easy to seal location between the seal frame and the manifold.

  16. Python fiber-optic seal

    SciTech Connect

    Ystesund, K.; Bartberger, J.; Brusseau, C.; Fleming, P.; Insch, K.; Tolk, K.

    1993-12-31

    Sandia National Laboratories (SNL) has developed a high-security fiber-optic seal that incorporates tamper-resistance features not available in commercial fiber-optic seals. The Python Seal is a passive fiber-optic loop seal designed to give indication of unauthorized entry. The seal includes a fingerprint feature that provides seal identity information in addition to the unique fiber-optic pattern created when the seal is installed. The fiber-optic cable used for the seal loop is produced with tamper-resistant features that increase the difficulty of attacking this component of a seal. A Seal Reader has been developed that records the seal signature and the fingerprint feature of the seal. A Correlator software program compares seal images to establish a match or mismatch. SNL also is developing a Polaroid Reader to permit hard copies of the seal patterns to be obtained directly from the seal.

  17. Rotary kiln seal

    DOEpatents

    Drexler, Robert L.

    1992-01-01

    A rotary seal used to prevent the escape of contaminates from a rotating kiln incinerator. The rotating seal combines a rotating disc plate which is attached to the rotating kiln shell and four sets of non-rotating carbon seal bars housed in a primary and secondary housing and which rub on the sides of the disc. A seal air system is used to create a positive pressure in a chamber between the primary and secondary seals to create a positive air flow into the contaminated gas chamber. The seal air system also employs an air inlet located between the secondary and tertiary seals to further insure that no contaminates pass the seal and enter the external environment and to provide makeup air for the air which flows into the contaminated gas chamber. The pressure exerted by the seal bars on the rotating disc is controlled by means of a preload spring. The seal is capable of operating in a thermally changing environment where the both radial expansion and axial movement of the rotating kiln do not result in the failure of the seal.

  18. Zero leakage sealings

    NASA Astrophysics Data System (ADS)

    Kotesovec, Bernhard; Steinrück, Herbert

    2010-11-01

    The piston rod of a reciprocating compressor is sealed with elastic cylindrical sealing elements. Across the sealings the pressure drops from the operating pressure to the ambient pressure. The lubrication gap between the elastic sealing and reciprocating piston rod is studied with the aim to find conditions of a leakage free sealing. The flow in the lubrication gap and the elastic deformation of the sealing are determined simultaneously. The net-flow during one cycle of the reciprocating piston rod is calculated. It turns out that maintaining zero leakage is very sensible. Indeed the outbound flow during out-stroke has to be equal the inbound flow during the in-stroke. By prescribing a special shape of the undeformed sealing zero leakage can be attained - at least theoretically for certain operating conditions. It turns out that temperature dependent material data and a model for cavitation is necessary. The model, its numerical implementation and results will be discussed.

  19. COMPRESSION SEAL AND SEALING MATERIAL THEREFOR

    DOEpatents

    Branin, T.G.

    1962-05-29

    This patent relates to compression seal and more particularly to a seaiing material therefor. The sealing surface is a coating consisting of alternate layers of gold and of a non-gold metal having similar plastic flow properties under pressure as gold. The coating is substantially free from oxidation effects when exposed to ambient atmosphere and does not become brittle when worked, as in a valve. (AEC)

  20. Heat loss in air of an Antarctic marine mammal, the Weddell seal.

    PubMed

    Mellish, Jo-Ann; Hindle, Allyson; Skinner, John; Horning, Markus

    2015-01-01

    The conflicting needs of homeostasis in air versus water complicate our understanding of thermoregulation in marine mammals. Large-scale modeling efforts directed at predicting the energetic impact of changing sea ice conditions on polar ecosystems require a better understanding of thermoregulation in air of free-ranging animals. We utilized infrared imaging as an indirect approach to determine surface temperatures of dry, hauled-out Weddell seals (Leptonychotes weddellii, n = 35) of varying age and body condition during the Antarctic summer. The study groups provided a fivefold range in body mass and a threefold range in blubber depth. Surface temperature (T s) did not vary by body region (head, shoulder, axilla, torso, hip, flippers). Average seal T s (mean 13.9 ± 11.2 °C) was best described through a combination of the physical traits of body mass and environmental variables of ambient temperature T air, and wind speed. Additional factors of ice temperature (T ice), relative humidity and cloud cover did not improve the model. Heat transfer model estimates suggested that radiation contributed 56.6 ± 7.7 % of total heat loss. Convection and conduction accounted for the remaining 15.7 ± 12.3 and 27.7 ± 9.3 %, respectively. Heat loss by radiation was primarily influenced by body mass and wind speed, whereas convective heat loss was influenced primarily by blubber depth and wind speed. Conductive heat loss was modeled largely as a function of physical traits of mass and blubber depth rather than any environmental covariates, and therefore was substantially higher in animals in leaner condition. PMID:25378218

  1. Shaft seal system

    DOEpatents

    Kapich, Davorin D.

    1985-01-01

    A shaft seal system is disclosed for isolating two regions of different fluid mediums through which a rotatable shaft extends. The seal system includes a seal housing through which the shaft extends and which defines an annular land and an annular labyrinth both of which face on the shaft so that each establishes a corresponding fluid sealing annulus. A collection cavity is formed in communication with the annular sealing spaces, and fluids compatible with the fluids in each of the two regions to be isolated are introduced, respectively, into the annular sealing spaces and collected in the collection cavity from which the fluid mixture is removed and passed to a separator which separates the fluids and returns them to their respective annular sealing spaces in a recycling manner. In the illustrated embodiment, the isolated fluid mediums comprise a liquid region and a gas region. Gas is removed from the gas region and passed through a purifier and a gas pump operative to introduce the purified gas through the labyrinth sealing annulus to the collection cavity. After passing to the separator, the separated gas is passed through a dryer from which the dried gas is caused to pass through the labyrinth sealing annulus into the collection cavity independently of the purified gas so as to insure isolation of the gas region in the event of sealing gas pump malfunction.

  2. Natural Tracers and Multi-Scale Assessment of Caprock Sealing Behavior: A Case Study of the Kirtland Formation, San Juan Basin

    SciTech Connect

    Jason Heath; Brian McPherson; Thomas Dewers

    2011-03-15

    The assessment of caprocks for geologic CO{sub 2} storage is a multi-scale endeavor. Investigation of a regional caprock - the Kirtland Formation, San Juan Basin, USA - at the pore-network scale indicates high capillary sealing capacity and low permeabilities. Core and wellscale data, however, indicate a potential seal bypass system as evidenced by multiple mineralized fractures and methane gas saturations within the caprock. Our interpretation of {sup 4}He concentrations, measured at the top and bottom of the caprock, suggests low fluid fluxes through the caprock: (1) Of the total {sup 4}He produced in situ (i.e., at the locations of sampling) by uranium and thorium decay since deposition of the Kirtland Formation, a large portion still resides in the pore fluids. (2) Simple advection-only and advection-diffusion models, using the measured {sup 4}He concentrations, indicate low permeability ({approx}10-20 m{sup 2} or lower) for the thickness of the Kirtland Formation. These findings, however, do not guarantee the lack of a large-scale bypass system. The measured data, located near the boundary conditions of the models (i.e., the overlying and underlying aquifers), limit our testing of conceptual models and the sensitivity of model parameterization. Thus, we suggest approaches for future studies to better assess the presence or lack of a seal bypass system at this particular site and for other sites in general.

  3. Contracting/expanding self-sealing cryogenic tube seals

    NASA Technical Reports Server (NTRS)

    Jia, Lin X. (Inventor)

    1997-01-01

    Contracting/expanding self-sealing cryogenic tube seals are disclosed which use the different properties of thermal contraction and expansion of selected dissimilar materials in accord with certain design criteria to yield self-tightening seals via sloped-surface sealing. The seals of the subject invention are reusable, simple to assemble, adaptable to a wide variety of cryogenic applications.

  4. Contracting/expanding self-sealing cryogenic tube seals

    NASA Technical Reports Server (NTRS)

    Jia, Lin X. (Inventor)

    1997-01-01

    Contracting/expanding self-sealing cryogenic tube seals are disclosed which use the different properties of thermal contraction and expansion of selected dissimilar materials in accord with certain design criteria to yield self-tightening seals via sloped-surface sealing. The seals of the subject invention are reusable, simple to assemble, and adaptable to a wide variety of cryogenic applications.

  5. Mechanically expandable annular seal

    DOEpatents

    Gilmore, Richard F.

    1983-01-01

    A mechanically expandable annular reusable seal assembly to form an annular hermetic barrier between two stationary, parallel, and planar containment surfaces. A rotatable ring, attached to the first surface, has ring wedges resembling the saw-tooth array of a hole saw. Matching seal wedges are slidably attached to the ring wedges and have their motion restricted to be perpendicular to the second surface. Each seal wedge has a face parallel to the second surface. An annular elastomer seal has a central annular region attached to the seal wedges' parallel faces and has its inner and outer circumferences attached to the first surface. A rotation of the ring extends the elastomer seal's central region perpendicularly towards the second surface to create the fluidtight barrier. A counterrotation removes the barrier.

  6. Mechanically expandable annular seal

    DOEpatents

    Gilmore, R.F.

    1983-07-19

    A mechanically expandable annular reusable seal assembly to form an annular hermetic barrier between two stationary, parallel, and planar containment surfaces is described. A rotatable ring, attached to the first surface, has ring wedges resembling the saw-tooth array of a hole saw. Matching seal wedges are slidably attached to the ring wedges and have their motion restricted to be perpendicular to the second surface. Each seal wedge has a face parallel to the second surface. An annular elastomer seal has a central annular region attached to the seal wedges' parallel faces and has its inner and outer circumferences attached to the first surface. A rotation of the ring extends the elastomer seal's central region perpendicularly towards the second surface to create the fluid tight barrier. A counter rotation removes the barrier. 6 figs.

  7. Damped flexible seal

    DOEpatents

    DuBois, Neil J.; Amaral, Antonio M.

    1992-10-27

    A damped flexible seal assembly for a torpedo isolates the tailcone thereof rom vibrational energy present in the drive shaft assembly. A pair of outside flanges, each of which include an inwardly facing groove and an O-ring constrained therein, provide a watertight seal against the outer non-rotating surface of the drive shaft assembly. An inside flange includes an outwardly-facing groove and an O-ring constrained therein, and provides a watertight seal against the inner surface of the tail cone. Two cast-in-place elastomeric seals provide a watertight seal between the flanges and further provide a damping barrier between the outside flanges and the inside flanges for damping vibrational energy present in the drive shaft assembly before the energy can reach the tailcone through the seal assembly.

  8. Layered seal for turbomachinery

    DOEpatents

    Sarawate, Neelesh Nandkumar; Morgan, Victor John; Weber, David Wayne

    2015-11-20

    The present application provides seal assemblies for reducing leakages between adjacent components of turbomachinery. The seal assemblies may include outer shims, and at least a portion of the outer shims may be substantially impervious. At least one of the outer shims may be configured for sealing engagement with seal slots of the adjacent components. The seal assemblies may also include at least one of an inner shim and a filler layer positioned between the outer shims. The at least one inner shim may be substantially solid and the at least one filler layer may be relatively porous. The seal assemblies may be sufficiently flexible to account for misalignment between the adjacent components, sufficiently stiff to meet assembly requirements, and sufficiently robust to operating meet requirements associated with turbomachinery.

  9. Seals Code Development Workshop

    NASA Technical Reports Server (NTRS)

    Hendricks, Robert C. (Compiler); Liang, Anita D. (Compiler)

    1996-01-01

    Seals Workshop of 1995 industrial code (INDSEAL) release include ICYL, GCYLT, IFACE, GFACE, SPIRALG, SPIRALI, DYSEAL, and KTK. The scientific code (SCISEAL) release includes conjugate heat transfer and multidomain with rotordynamic capability. Several seals and bearings codes (e.g., HYDROFLEX, HYDROTRAN, HYDROB3D, FLOWCON1, FLOWCON2) are presented and results compared. Current computational and experimental emphasis includes multiple connected cavity flows with goals of reducing parasitic losses and gas ingestion. Labyrinth seals continue to play a significant role in sealing with face, honeycomb, and new sealing concepts under investigation for advanced engine concepts in view of strict environmental constraints. The clean sheet approach to engine design is advocated with program directions and anticipated percentage SFC reductions cited. Future activities center on engine applications with coupled seal/power/secondary flow streams.

  10. Dynamic sealing principles

    NASA Technical Reports Server (NTRS)

    Zuk, J.

    1976-01-01

    The fundamental principles governing dynamic sealing operation are discussed. Different seals are described in terms of these principles. Despite the large variety of detailed construction, there appear to be some basic principles, or combinations of basic principles, by which all seals function, these are presented and discussed. Theoretical and practical considerations in the application of these principles are discussed. Advantages, disadvantages, limitations, and application examples of various conventional and special seals are presented. Fundamental equations governing liquid and gas flows in thin film seals, which enable leakage calculations to be made, are also presented. Concept of flow functions, application of Reynolds lubrication equation, and nonlubrication equation flow, friction and wear; and seal lubrication regimes are explained.

  11. Compliant Turbomachine Sealing

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Braun, M. J.; Deng, D.; Hendricks, J. A.

    2011-01-01

    Sealing interface materials and coatings are sacrificial, giving up their integrity for the benefit of the component. Seals that are compliant while still controlling leakage, dynamics, and coolant flows are sought to enhance turbomachine performance. Herein we investigate the leaf-seal configuration. While the leaf seal is classified as contacting, a ready modification using the leaf-housing arrangement in conjunction with an interface film rider (a bore seal, for example) provides for a film-riding noncontact seal. The leaf housing and leaf elements can be made from a variety of materials from plastic to ceramic. Four simplistic models are used to identify the physics essential to controlling leakage. Corroborated by CFD, these results provide design parameters for applications to within reasonable engineering certainty. Some potential improvements are proposed.

  12. Sodium sulfur battery seal

    DOEpatents

    Mikkor, Mati

    1981-01-01

    This disclosure is directed to an improvement in a sodium sulfur battery construction in which a seal between various battery compartments is made by a structure in which a soft metal seal member is held in a sealing position by holding structure. A pressure applying structure is used to apply pressure on the soft metal seal member when it is being held in sealing relationship to a surface of a container member of the sodium sulfur battery by the holding structure. The improvement comprises including a thin, well-adhered, soft metal layer on the surface of the container member of the sodium sulfur battery to which the soft metal seal member is to be bonded.

  13. Air Force seal activities

    NASA Technical Reports Server (NTRS)

    Mayhew, Ellen R.

    1994-01-01

    Seal technology development is an important part of the Air Force's participation in the Integrated High Performance Turbine Engine Technology (IHPTET) initiative, the joint DOD, NASA, ARPA, and industry endeavor to double turbine engine capabilities by the turn of the century. Significant performance and efficiency improvements can be obtained through reducing internal flow system leakage, but seal environment requirements continue to become more extreme as the engine thermodynamic cycles advance towards these IHPTET goals. Brush seal technology continues to be pursued by the Air Force to reduce leakage at the required conditions. Likewise, challenges in engine mainshaft air/oil seals are also being addressed. Counter-rotating intershaft applications within the IHPTET initiative involve very high rubbing velocities. This viewgraph presentation briefly describes past and current seal research and development programs and gives a summary of seal applications in demonstrator and developmental engine testing.

  14. Double face sealing device

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce C. (Inventor)

    1991-01-01

    A double face sealing device for mounting between two surfaces to provide an airtight and fluid-tight seal between a closure member bearing one of the surfaces and a structure or housing bearing the other surface which extends around the opening or hatchway to be closed. The double face sealing device includes a plurality of sections or segments mounted to one of the surfaces, each having a main body portion, a pair of outwardly extending and diverging, cantilever, spring arms, and a pair of inwardly extending and diverging, cantilever, spring arms, an elastomeric cover on the distal, free, ends of the outwardly extending and diverging spring arms, and an elastomeric cover on the distal, free, ends of the inwardly extending and diverging spring arms. The double face sealing device has application or use in all environments requiring a seal, but is particularly useful to seal openings or hatchways between compartments of spacecraft or aircraft.

  15. Grayloc seal static tests

    SciTech Connect

    Leisher, W.B.; Biffle, J.H.

    1983-02-01

    A series of evaluation tests was performed on Grayloc seals. Helium service and standard seals, size 292, were used. Measurements were made of axial force and motion, diameter, hoop and axial strain, and helium leak rate. Leak rates were in the 10/sup -6/ atm cc/s range for the helium service seals. Pretest analytical calculations agreed reasonably well with measured makeup forces and deflections.

  16. Liquid Annular Seal Research

    NASA Technical Reports Server (NTRS)

    Palazzolo, Alan B.; Venkataraman, Balaji; Padavala, Sathya S.; Ryan, Steve; Vallely, Pat; Funston, Kerry

    1996-01-01

    This paper highlights the accomplishments on a joint effort between NASA - Marshall Space Flight Center and Texas A and M University to develop accurate seal analysis software for use in rocket turbopump design, design audits and trouble shooting. Results for arbitrary clearance profile, transient simulation, thermal effects solution and flexible seal wall model are presented. A new solution for eccentric seals based on cubic spline interpolation and ordinary differential equation integration is also presented.

  17. Seals Flow Code Development

    NASA Technical Reports Server (NTRS)

    1991-01-01

    In recognition of a deficiency in the current modeling capability for seals, an effort was established by NASA to develop verified computational fluid dynamic concepts, codes, and analyses for seals. The objectives were to develop advanced concepts for the design and analysis of seals, to effectively disseminate the information to potential users by way of annual workshops, and to provide experimental verification for the models and codes under a wide range of operating conditions.

  18. Retractable environmental seal

    NASA Technical Reports Server (NTRS)

    Dettling, J. R. (Inventor)

    1979-01-01

    A retractable environmental seal for use in sealing the opening of the exit cone for a rocket nozzle is described. A diaphragm-like cover having a central region adapted to be seated in sealing relation with the periphery of the opening is discussed. Radially extended failure zones for facilitating a pressure-induced rupture of the cover, and a plurality of angularly spaced tension springs connected with the peripheral portion of the cover are characterized.

  19. Liquid zone seal

    DOEpatents

    Klebanoff, Leonard E.

    2001-01-01

    A seal assembly that provides a means for establishing multiple pressure zones within a system. The seal assembly combines a plate extending from the inner wall of a housing or inner enclosure that intersects with and is immersed in the fluid contained in a well formed in a tray contained within the enclosure. The fluid is a low vapor pressure oil, chemically inert and oxidation resistant. The use of a fluid as the sealing component provides a seal that is self-healing and mechanically robust not subject to normal mechanical wear, breakage, and formation of cracks or pinholes and decouples external mechanical vibrations from internal structural members.

  20. Control line sealing connection

    SciTech Connect

    Tohill, H.O.

    1984-07-10

    A sealing connection for the passage of a fluid control line through adjoining members is claimed. The connection comprises a metallic tubular sealing element provided with tapered end portions, each end having internal frusto-conical surfaces and external frusto-conical surfaces in coaxial alignment with the bore through the element. The external frusto-conical surfaceas provide metal-to-metal sealing with aligned frusto-conical seating surfaces in opposed pockets formed in aligned portions of the control line at their respective openings at the adjoining surfaces of the adjoined member. The tubular sealing element is subjected to axial compression between the frusto-conical pocket seating surfaces when the adjoined members are bolted tightly together which results in deformation of its tapered end portions to provide metal-to-metal sealing with the adjoined members which is effective to seal against both internal and external fluid pressurization of the control line and without internally obstructing or restricting the control line. Secondary sealing is provided by elastomeric O-ring seals mounted in circumferential annular grooves formed in the exterior of the tubular sealing element.

  1. Repository seals requirements study

    SciTech Connect

    1997-11-03

    The Yucca Mountain Site Characterization Project, managed by the Civilian Radioactive Waste Management System (CRWMS) Management and Operating Contractor (M and O) is conducting investigations to support the Viability Assessment and the License Application for a high-level nuclear waste repository at Yucca Mountain, Nevada. The sealing subsystem is part of the Yucca Mountain Waste Isolation System. The Yucca Mountain Site Characterization Project is currently evaluating the role of the sealing subsystem (shaft, ramp and exploratory borehole seals) in achieving the overall performance objectives for the Waste Isolation System. This report documents the results of those evaluations. This report presents the results of a repository sealing requirements study. Sealing is defined as the permanent closure of the shafts, ramps, and exploratory boreholes. Sealing includes those components that would reduce potential inflows above the repository, or that would divert flow near the repository horizon to allow vertical infiltration to below the repository. Sealing of such features as emplacement drifts was not done in this study because the current capability to calculate fracture flow into the drifts is not sufficiently mature. The objective of the study is to provide water or air flow performance based requirements for shafts, ramps, and exploratory boreholes located near the repository. Recommendations, as appropriate, are provided for developing plans, seals component testing, and other studies relating to sealing.

  2. Compliant Foil Seal Investigations

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret; Delgado, Irebert

    2003-01-01

    NASA Glenn Research Center has been working with Mohawk Innovative Technology, Inc. (MiTi) to develop a Compliant Foil Seal for use in gas turbine engines. MiTi was awarded phase I and phase II SBIR contracts to analyze, develop, and test foil seals. As part of the Phase II contract, MiTi delivered an 8.5 inch diameter foil seal to NASA GRC for testing. Today I will be presenting some results of testing the 8.5 inch foil seal at NASA.

  3. Foil Face Seal Testing

    NASA Technical Reports Server (NTRS)

    Munson, John

    2009-01-01

    In the seal literature you can find many attempts by various researchers to adapt film riding seals to the gas turbine engine. None have been successful, potential distortion of the sealing faces is the primary reason. There is a film riding device that does accommodate distortion and is in service in aircraft applications, namely the foil bearing. More specifically a foil thrust bearing. These are not intended to be seals, and they do not accommodate large axial movement between shaft & static structure. By combining the 2 a unique type of face seal has been created. It functions like a normal face seal. The foil thrust bearing replaces the normal primary sealing surface. The compliance of the foil bearing allows the foils to track distortion of the mating seal ring. The foil seal has several perceived advantages over existing hydrodynamic designs, enumerated in the chart. Materials and design methodology needed for this application already exist. Also the load capacity requirements for the foil bearing are low since it only needs to support itself and overcome friction forces at the antirotation keys.

  4. Ceramic brush seals development

    NASA Technical Reports Server (NTRS)

    Howe, Harold

    1994-01-01

    The following topics are discussed in this viewgraph presentation: ceramic brush seals, research and development, manufacturing, brazed assembly development, controlling braze flow, fiber selection, and braze results.

  5. Bidirectional Brush Seals

    NASA Technical Reports Server (NTRS)

    Hendricks, Robert C.; Wilson, Jack; Wu, Tom; Flower, Ralph

    1997-01-01

    Presented is a study of the use of a set of I.D./O.D. bidirectional press seals to reduce the leakage losses in a wave rotor. Relative to the baseline configuration, data indicate the use of brush seals enhanced wave rotor efficiency from 36 to 45 percent at low leakages (small rotor endwall gap spacings) and from 15 to 33 percent at high leakages (larger endwall gap spacings). These brush seals are capable of sealing positive or negative pressure drops with respect to the axial direction. Surface tribology for these tests suggested little evidence of grooving although the bristles appeared polished.

  6. Experimental Study on Leakage Flow in Labyrinth Seals with Asymmetric Geometries

    NASA Astrophysics Data System (ADS)

    Nishii, Kazufumi; Furukawa, Akinori; Watanabe, Satoshi; Miyake, Kunihiro

    2010-06-01

    The labyrinth seal is one of non-contact seals, which is used as a seal device of rotary machines from reasons of the lubrication free and small losses. So far, many researchers have investigated the characteristics and suitable geometries of labyrinth seals, though only one directional flow of the seal has been focused up to now. As flow direction in the seal becomes changeable depending on the gas-purge system and the inner pressure variation of machines for recent applications, a guideline of designing labyrinth seal with changeable flow directions is required. In the present report, effects of seal characteristics and internal flow behaviors on various shapes of asymmetric convexity in labyrinth seals are experimentally investigated and relations between pressure loss and convexity geometries are discussed for designing a suitable seal.

  7. Advanced bristle seals for gas turbine engines. Final report, May-November 1992

    SciTech Connect

    Cabe, J.L.

    1993-01-28

    A seven month proof-of-concept program was conducted for an advanced bristle seal, called a bush seal, for use in gas turbine engines. This program was performed as a Small Business Innovation Research (SBIR) Phase I project. Bush seal specimen and a full ring bush seal were designed, evaluated, and manufactured for testing. An analytical study of the potential of the bush seal relative to a labyrinth seal was conducted. Static and dynamic testing of the bush seal was performed to determine the behavior of the bristles under pressurization and during contact with a rotating labyrinth tooth. Stable behavior of the bristle elements was observed during static pressurization of a full ring bush seal. The dynamic testing of various configurations of bush seal against a rotating labyrinth tooth showed minimal wear of the bristles relative to a conventional labyrinth seal. the development and application of the bush seal concept to gas turbine engines has the potential of improving the engine's performance while decreasing the degradation of the seal performance over time.... Seal, Bush seal, Labyrinth seal, Gas turbine.

  8. Seal ring installation tool

    NASA Technical Reports Server (NTRS)

    Haselmaier, L. Haynes (Inventor)

    2004-01-01

    A seal ring tool that allows an installer to position a primary seal ring between hub ends of pipe flanges that are being assembled together. The tool includes a pivoting handle member and extension arms attached to the pivoting handle member. The ends of the arms have side indentation type longitudinal grooves angled toward one another for holding the primary seal ring in place between the hubs of respective pipes that are to be attached together. The arms of the tool can also have flat sides that can be used to abut against an optional second larger seal that is supported within a groove in one of the hub ends so that the second hub end can then be moved against the other side of the primary seal ring. Once the seal ring is positioned between the pipe hubs, the pipe hubs can be moved about the seal ring due to the flat sides of the arms of the tool. The tool eliminates the chances of damaging and contaminating seal rings being installed within pipe hubs that are being attached to one another.

  9. Seals and Scrolls.

    ERIC Educational Resources Information Center

    Macaulay, Sara Grove

    2000-01-01

    Describes an art unit in which students sculpt a signature seal out of clay and use Chinese brush painting techniques to paint a scroll. Discusses the seal and its historical use in China. Lists materials needed and explains the procedure. (CMK)

  10. MOLDED SEALING ELEMENT

    DOEpatents

    Bradford, B.W.; Skinner, W.J.

    1959-03-24

    Molded sealing elements suitable for use under conditions involving exposure to uranium hexafluoride vapor are described. Such sealing elements are made by subjecting graphitic carbons to a preliminary treatment with uranium hexafluoride vapor, and then incorporating polytetrafluorethylene in them. The resulting composition has good wear resistant and frictional properties and is resistant to disintegration by uranium hexafluoride over long periods of exposure.

  11. Sodium sulfur battery seal

    DOEpatents

    Topouzian, Armenag

    1980-01-01

    This invention is directed to a seal for a sodium sulfur battery in which a flexible diaphragm sealing elements respectively engage opposite sides of a ceramic component of the battery which separates an anode compartment from a cathode compartment of the battery.

  12. Resilient Braided Rope Seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor); Kren, Lawrence A. (Inventor)

    2000-01-01

    A resilient braided rope seal for use in high temperature applications includes a center core of fibers. a resilient canted spring member supporting the core and at least one layer of braided sheath fibers tightly packed together overlying the spring member. The seal provides both improved load bearing and resiliency. Permanent set and hysteresis are greatly reduced.

  13. Flexible Seal Accommodates Part Mismatch

    NASA Technical Reports Server (NTRS)

    Bobb, I.

    1983-01-01

    Chain of plates embedded in flexible seal enables it to withstand side loading of 2,300 psi (116MPa) while sealing gap of up to 0.5 inch (13 mm) between cylindrical chamber wall and test fixture. Pressure-actuated seal along inner edge forces seal into contact even though cylinder wall becomes eccentric as cylinder pressure increases. Seal has many industrial applications, particularly where heat or pressure causes distortion of chamber being sealed.

  14. SSME interstage seal research

    NASA Technical Reports Server (NTRS)

    Childs, D. W.

    1984-01-01

    Test results comprising direct and transverse force coefficients and leakage coefficients are reported for six seal configurations. All seals tested use the same smooth rotor and have the same constant minimum clearance. The following stator configurations were tested: (1) Smooth, (2) knurled pattern, (3) axially-grooved pattern with end seals, (4) diamond-grid roughened, (5) diamond-grid roughened with end seals, and (6) round-hole pattern. Comparison of the seals shows the Knurled-pattern stator to be the stiffest and the round-hole pattern stator to yield the largest net damping and the least leakage. The theory of reference is shown to substantially underestimate the stiffness and effective-added-mass coefficients, but do a reasonable job in predicting the net-damping-force coefficient.

  15. High temperature hydraulic seals

    NASA Astrophysics Data System (ADS)

    Williams, K. R.

    1993-05-01

    This program investigated and evaluated high temperature hydraulic sealing technology, including seals, fluids, and actuator materials. Test limits for fluid pressure and temperature were 8000 psi and 700 F respectively. The original plan to investigate CTFE fluid at 350 F as well as other fluids at higher temperatures was reduced in scope to include only the higher temperature investigation. Seals were obtained from 11 manufacturers. Design requirements including materials, dimensions, clearances, and tolerances were established and test modules were constructed from the detail designs which were produced. Nine piston seals and one rod seal were tested at temperatures ranging from -65 to +600 F and pressures to 6000 psi. Fluid performance under these conditions was evaluated. Details of this activity and results of the effort are summarized in this report.

  16. Sealing in Turbomachinery

    NASA Technical Reports Server (NTRS)

    Chupp, Raymond E.; Hendricks, Robert C.; Lattime, Scott B.; Steinetz, Bruce M.

    2006-01-01

    Clearance control is of paramount importance to turbomachinery designers and is required to meet today's aggressive power output, efficiency, and operational life goals. Excessive clearances lead to losses in cycle efficiency, flow instabilities, and hot gas ingestion into disk cavities. Insufficient clearances limit coolant flows and cause interface rubbing, overheating downstream components and damaging interfaces, thus limiting component life. Designers have put renewed attention on clearance control, as it is often the most cost effective method to enhance system performance. Advanced concepts and proper material selection continue to play important roles in maintaining interface clearances to enable the system to meet design goals. This work presents an overview of turbomachinery sealing to control clearances. Areas covered include: characteristics of gas and steam turbine sealing applications and environments, benefits of sealing, types of standard static and dynamics seals, advanced seal designs, as well as life and limitations issues.

  17. Rotary shaft seal

    DOEpatents

    Langebrake, Clair O.

    1984-01-01

    The invention is a novel rotary shaft seal assembly which provides positive-contact sealing when the shaft is not rotated and which operates with its sealing surfaces separated by a film of compressed ambient gas whose width is independent of the speed of shaft rotation. In a preferred embodiment, the assembly includes a disc affixed to the shaft for rotation therewith. Axially movable, non-rotatable plates respectively supported by sealing bellows are positioned on either side of the disc to be in sealing engagement therewith. Each plate carries piezoelectric transducer elements which are electrically energized at startup to produce films of compressed ambient gas between the confronting surfaces of the plates and the disc. Following shutdown of the shaft, the transducer elements are de-energized. A control circuit responds to incipient rubbing between the plate and either disc by altering the electrical input to the transducer elements to eliminate rubbing.

  18. Rotary shaft seal

    DOEpatents

    Langebrake, C.O.

    1984-01-01

    The invention is a novel rotary shaft seal assembly which provides positive-contact sealing when the shaft is not rotated and which operates with its sealing surfaces separated by a film of compressed ambient gas whose width is independent of the speed of shaft rotation. In a preferred embodiment, the assembly includes a disc affixed to the shaft for rotation therewith. Axially movable, non-rotatable plates respectively supported by sealing bellows are positioned on either side of the disc to be in sealing engagement therewith. Each plate carries piezoelectric transucer elements which are electrically energized at startup to produce films of compressed ambient gas between the confronting surfaces of the plates and the disc. Following shutdown of the shaft, the transducer elements are de-energized. A control circuit responds to incipient rubbing between the plate and either disc by altering the electrical input to the transducer elements to eliminate rubbing.

  19. Repository seals requirement study

    SciTech Connect

    1997-11-03

    The Yucca Mountain Site Characterization Project, managed by the Civilian Radioactive Waste Management System (CRWMS) Management and Operating Contractor (M and O) is conducting investigations to support the Viability Assessment and the License Application for a high-level nuclear waste repository at Yucca Mountain, Nevada. The sealing subsystem is part of the Yucca Mountain Waste Isolation System. The Yucca Mountain Site Characterization Project is currently evaluating the role of the sealing subsystem (shaft, ramp and exploratory borehole seals) in achieving the overall performance objectives for the Waste Isolation System. This report documents the results of those evaluations. The objective of the study is to provide water or air flow performance based requirements for shafts, ramps, and exploratory boreholes located near the repository. Recommendations, as appropriate, are provided for developing plans, seals component testing, and other studies relating to sealing.

  20. Transmission seal development

    NASA Technical Reports Server (NTRS)

    Brien, M.

    1977-01-01

    An experimental evaluation was performed on a high-speed (72.9 m/s, 14,349 ft/min) transmission seal of the synergistic type. During testing of the seal, oil leakage occurred at positive bearing cavity pressures. Modifications were made in an attempt to eliminate the leakage but none were completely successful. Leakage appears to be the result of questionable positioning of the sealing elements resulting in inadequate shaft contact by the oil side sealing element. This condition may be related to the nonsymmetrical shape of the elastomeric retainer and to dimensional changes caused by swelling of the elastomeric retainer from exposure to the sealed fluid. Indications of a speed dependent leakage characteristic were also observed.

  1. Seals Flow Code Development 1993

    NASA Technical Reports Server (NTRS)

    Liang, Anita D. (Compiler); Hendricks, Robert C. (Compiler)

    1994-01-01

    Seals Workshop of 1993 code releases include SPIRALI for spiral grooved cylindrical and face seal configurations; IFACE for face seals with pockets, steps, tapers, turbulence, and cavitation; GFACE for gas face seals with 'lift pad' configurations; and SCISEAL, a CFD code for research and design of seals of cylindrical configuration. GUI (graphical user interface) and code usage was discussed with hands on usage of the codes, discussions, comparisons, and industry feedback. Other highlights for the Seals Workshop-93 include environmental and customer driven seal requirements; 'what's coming'; and brush seal developments including flow visualization, numerical analysis, bench testing, T-700 engine testing, tribological pairing and ceramic configurations, and cryogenic and hot gas facility brush seal results. Also discussed are seals for hypersonic engines and dynamic results for spiral groove and smooth annular seals.

  2. Reactor cavity seal ring

    SciTech Connect

    Hankinson, M.F.

    1986-04-22

    A hydrostatic seal is described for sealing an annular gap between two flat substantially horizontal coplanar surfaces comprising, in combination: a generally flat annular plate of a width sufficient to span a gap between two surfaces: compressible annular sealing means disposed on the bottom surface of the flat annular plate for sealingly engaging the two flat surfaces in response to a downward force exerted on the plate; and fastening means, distributed along the center line of the plate, for releasably fastening the plate in a position to span the gap to be sealed and exert a downward force on the plate, each fastening means including a pair of elongated members of a size to fit into the gap to be sealed, means for mounting the members on the bottom surface of the plate so that at least a portion of each member is radially moveable in a direction toward a respective one of the vertical side surfaces defining the gap to be sealed to engage same and so that the plate is moveable relative to the members in a downward direction in response to hydrostatic pressure applied to the upper surface of the plate when the members are engaging the vertical side surfaces of an annular gap, and an actuating means, mounted on the plate for movement therewith in response to hydrostatic pressure, for radially moving the members, the actuating means extending through a bore in the plate to the upper surface of the plate.

  3. Bellow seal and anchor

    DOEpatents

    Mansure, Arthur J.

    2001-01-01

    An annular seal is made of a collapsible bellows. The bellows can function as an anchor or a seal and is easily set into position using relative component movement. The bellows folds can be slanted and their outer sealing edges can have different profiles to meet expected conditions. The bellows is expanded for insertion to reduce its outer dimension and sets by compaction as a result of relative movement. The bellows can be straight or tapered and is settable with a minimal axial force.

  4. Gland With Cantilever Seal

    NASA Technical Reports Server (NTRS)

    Melton, Patrick B.

    1989-01-01

    Single-piece gland forms tight seal on probe or tube containing liquid or gas at high pressure. Gland and probe align as assembled by simple torquing procedure. Disconnected easily and reused at same site. Made from any of wide variety of materials so compatible with application. Cantilever ring at top of gland bites into wall of tube or probe, sealing it. Wall of tube or probe must be thick enough to accommodate deformation without rupturing. Maximum deformation designed in coordination with seating and deformation of boss or conical seal.

  5. Noncontacting Finger Seal

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P. (Inventor); Steinetz, Bruce M. (Inventor)

    2004-01-01

    An annular finger seal is adapted to be interposed between a high pressure upstream region and a lower pressure downstream region to provide noncontact sealing along a rotatable member. The finger seal comprises axially juxtaposed downstream and upstream finger elements, each having integrally spaced fingers. The downstream fingers each have a lift pad, whereas the upstream fingers lack a pad. Each pad extends in a downstream direction. Each upstream finger is spaced from the rotating member a greater distance than each pad. Upon sufficient rotational speed of the rotating member, each pad is operative to lift and ride on a thin film of fluid intermediate the rotating member and the Pad.

  6. SEALING SIMULATED LEAKS

    SciTech Connect

    Michael A. Romano

    2004-09-01

    This report details the testing equipment, procedures and results performed under Task 7.2 Sealing Simulated Leaks. In terms of our ability to seal leaks identified in the technical topical report, Analysis of Current Field Data, we were 100% successful. In regards to maintaining seal integrity after pigging operations we achieved varying degrees of success. Internal Corrosion defects proved to be the most resistant to the effects of pigging while External Corrosion proved to be the least resistant. Overall, with limitations, pressure activated sealant technology would be a viable option under the right circumstances.

  7. Damping seals for turbomachinery

    NASA Technical Reports Server (NTRS)

    Vonpragenau, G. L.

    1985-01-01

    Rotor whirl stabilization of high performance turbomachinery which operates at supercritical speed is discussed. Basic whirl driving forces are reviewed. Stabilization and criteria are discussed. Damping seals are offered as a solution to whirl and high vibration problems. Concept, advantages, retrofitting, and limits of damping seals are explained. Dynamic and leakage properties are shown to require a rough stator surface for stability and efficiency. Typical seal characteristics are given for the case of the high pressure oxidizer turbopump of the Space Shuttle. Ways of implementation and bearing load effects are discussed.

  8. Multilayer compressive seal for sealing in high temperature devices

    DOEpatents

    Chou, Yeong-Shyung; Stevenson, Jeffry W.

    2007-08-21

    A mica based compressive seal has been developed exhibiting superior thermal cycle stability when compared to other compressive seals known in the art. The seal is composed of compliant glass or metal interlayers and a sealing (gasket) member layer composed of mica that is infiltrated with a glass forming material, which effectively reduces leaks within the seal. The compressive seal shows approximately a 100-fold reduction in leak rates compared with previously developed hybrid seals after from 10 to about 40 thermal cycles under a compressive stress of from 50 psi to 100 psi at temperatures in the range from 600.degree. C. to about 850.degree. C.

  9. Engine sealing and lubrication systems

    NASA Technical Reports Server (NTRS)

    Zuk, J.

    1975-01-01

    Engine sealing programs are discussed which are directed toward the two major classes of engine seals: engine shaft seals and primary gas path seals. In addition, some concepts and results from fundamental lubrication research, as it pertains to the lubrication of bearings, are presented.

  10. High Temperature Metallic Seal Development

    NASA Astrophysics Data System (ADS)

    Datta, Amit; More, D. Greg

    2002-10-01

    A high temperature static seal capable of long term operation at temperature ranging from 1400 F to 1800 F is presented. The contents include: 1) Development approach; 2) Stress relaxation curves; 3) High temperature seal test rig; 4) High temperature seal design; and 5) High temperature seal testing. This paper is in viewgraph form.

  11. Turbine seal assembly

    DOEpatents

    Little, David A.

    2013-04-16

    A seal assembly that limits gas leakage from a hot gas path to one or more disc cavities in a turbine engine. The seal assembly includes a seal apparatus that limits gas leakage from the hot gas path to a respective one of the disc cavities. The seal apparatus comprises a plurality of blade members rotatable with a blade structure. The blade members are associated with the blade structure and extend toward adjacent stationary components. Each blade member includes a leading edge and a trailing edge, the leading edge of each blade member being located circumferentially in front of the blade member's corresponding trailing edge in a direction of rotation of the turbine rotor. The blade members are arranged such that a space having a component in a circumferential direction is defined between adjacent circumferentially spaced blade members.

  12. Flexible cloth seal assembly

    DOEpatents

    Bagepalli, Bharat Sampathkumar; Taura, Joseph Charles; Aksit, Mahmut Faruk; Demiroglu, Mehmet; Predmore, Daniel Ross

    1999-01-01

    A seal assembly having a flexible cloth seal which includes a shim assemblage surrounded by a cloth assemblage. A first tubular end portion, such as a gas turbine combustor, includes a longitudinal axis and has smooth and spaced-apart first and second surface portions defining a notch therebetween which is wider at its top than at its bottom and which extends outward from the axis. The second surface portion is outside curved, and a first edge of the cloth seal is positioned in the bottom of the notch. A second tubular end portion, such as a first stage nozzle, is located near, spaced apart from, and coaxially aligned with, the first tubular end portion. The second tubular end portion has a smooth third surface portion which surrounds at least a portion of the first tubular end portion and which is contacted by the cloth seal.

  13. Gas turbine sealing apparatus

    SciTech Connect

    Marra, John Joseph; Wessell, Brian J.; Liang, George

    2013-03-05

    A sealing apparatus in a gas turbine. The sealing apparatus includes a seal housing apparatus coupled to a disc/rotor assembly so as to be rotatable therewith during operation of the gas turbine. The seal housing apparatus comprises a base member, a first leg portion, a second leg portion, and spanning structure. The base member extends generally axially between forward and aft rows of rotatable blades and is positioned adjacent to a row of stationary vanes. The first leg portion extends radially inwardly from the base member and is coupled to the disc/rotor assembly. The second leg portion is axially spaced from the first leg portion, extends radially inwardly from the base member, and is coupled to the disc/rotor assembly. The spanning structure extends between and is rigidly coupled to each of the base member, the first leg portion, and the second leg portion.

  14. Flexible cloth seal assembly

    DOEpatents

    Bagepalli, B.S.; Taura, J.C.; Aksit, M.F.; Demiroglu, M.; Predmore, D.R.

    1999-06-29

    A seal assembly is described having a flexible cloth seal which includes a shim assemblage surrounded by a cloth assemblage. A first tubular end portion, such as a gas turbine combustor, includes a longitudinal axis and has smooth and spaced-apart first and second surface portions defining a notch there between which is wider at its top than at its bottom and which extends outward from the axis. The second surface portion is outside curved, and a first edge of the cloth seal is positioned in the bottom of the notch. A second tubular end portion, such as a first stage nozzle, is located near, spaced apart from, and coaxially aligned with, the first tubular end portion. The second tubular end portion has a smooth third surface portion which surrounds at least a portion of the first tubular end portion and which is contacted by the cloth seal. 7 figs.

  15. Tamper indicating seal

    SciTech Connect

    Romero, Juan A.; Walker, Charles A.; Blair, Dianna S.; Bodmer, Connie C.

    2012-05-29

    Seals have a flexible wire that can be looped through a hasp-like device. The seals include a body having a recess, a plug insertable into the recess and a snap ring for fastening the plug to the body. The plug and/or body can have access holes for inserting the wire into the recess. "Teeth" on the outer diameter and through-holes through the thickness of the snap ring allow for passing the ends of the flexible wire from the recess through the snap ring. The ends of the wire can be folded back over the snap ring and into engagement with the teeth. Assembly of the seal causes the ends of the wire to be securely fastened between the teeth of the snap ring and the sidewall of the recess. Seals can include a plug and/or body made of a frangible material such as glass, ceramic, glass-ceramic or brittle polymer.

  16. Rotatable seal assembly

    DOEpatents

    Logan, Clinton M.; Garibaldi, Jack L.

    1982-01-01

    An assembly is provided for rotatably supporting a rotor on a stator so that vacuum chambers in the rotor and stator remain in communication while the chambers are sealed from ambient air, which enables the use of a ball bearing or the like to support most of the weight of the rotor. The apparatus includes a seal device mounted on the rotor to rotate therewith, but shiftable in position on the rotor while being sealed to the rotor as by an O-ring. The seal device has a flat face that is biased towards a flat face on the stator, and pressurized air is pumped between the faces to prevent contact between them while spacing them a small distance apart to avoid the inflow of large amounts of air between the faces and into the vacuum chambers.

  17. Ingestion resistant seal assembly

    DOEpatents

    Little, David A.

    2011-12-13

    A seal assembly limits gas leakage from a hot gas path to one or more disc cavities in a gas turbine engine. The seal assembly includes a seal apparatus associated with a blade structure including a row of airfoils. The seal apparatus includes an annular inner shroud associated with adjacent stationary components, a wing member, and a first wing flange. The wing member extends axially from the blade structure toward the annular inner shroud. The first wing flange extends radially outwardly from the wing member toward the annular inner shroud. A plurality of regions including one or more recirculation zones are defined between the blade structure and the annular inner shroud that recirculate working gas therein back toward the hot gas path.

  18. Split-ring seal

    NASA Technical Reports Server (NTRS)

    Gallo, E. A.

    1976-01-01

    Gland-type seal may be used with hydraulic and pneumatic actuators and similar equipment. It is designed for applications with partial vacuums and requires little space for installation and infrequent servicing.

  19. Conduit sealing system

    SciTech Connect

    Weinberg, R.A.

    1984-02-28

    The invention relates to an annular seal system designed for high pressure applications in subterranean wells. The annular seal system comprises a vertical stack of subassemblies. Each subassembly incorporates an annular sealing element formed from an elastomeric material, such as a perfluoroelastomer, which is provided with a truncated pear-shaped cross-sectional configuration having reversely curved axial side surfaces. The sealing element is abutted on each axial side by a uniform thickness annular bearing element formed from a thermoplastic such as a polyphenylene sulfide resin having good bearing properties. Each of the thermoplastic bearing elements is in turn abutted by an annular metallic restraining element having correspondingly shaped reversely curved axial side surfaces and defining an inverted truncated pear-shaped cross-sectional configuration.

  20. Ultra high vacuum seal arrangement

    SciTech Connect

    Flaherty, R.

    1981-08-11

    Arrangement for demountably sealing two concentric metallic tubes in an ultra high vacuum system which facilitates remote actuation is claimed. A tubular seal includes integral spaced lips which circumferentially engage the metallic tubes. The lips plastically deform the metallic tubes by mechanical forces resulting from a martensite to austenite transformation of the tubular seal upon application of a predetermined temperature. The sealing force is released upon application of another temperature which causes a transformation from the stronger austenite to the weaker martensite. Use of a dual acting sealing ring and driving ring circumferentially contacting the sealing ring is particularly applicable to sealing larger diameter concentric metallic members.

  1. Current developments in brush seals

    NASA Astrophysics Data System (ADS)

    Loewenthal, Bob

    1994-07-01

    The objective of the brush seal development program is to develop a comprehensive design methodology for brush seals using application requirements from engine manufacturers and experimental characterization of seal design and tribological pairs. The goals are to substantially lower leakage compared to labyrinth seals, seal life consistent with man-rated mission requirements, to investigate single and multiple staged brush seals, temperature up to 1200 F and surface speed up to 900 fps, and pressure drop across the seal of 50 psid. Test results are presented in viewgraph format.

  2. Ultra high vacuum seal arrangement

    DOEpatents

    Flaherty, Robert

    1981-01-01

    Arrangement for demountably sealing two concentric metallic tubes in an ultra high vacuum system which facilitates remote actuation. A tubular seal includes integral spaced lips which circumferentially engage the metallic tubes. The lips plastically deform the metallic tubes by mechanical forces resulting from a martensite to austenite transformation of the tubular seal upon application of a predetermined temperature. The sealing force is released upon application of another temperature which causes a transformation from the stronger austenite to the weaker martensite. Use of a dual acting sealing ring and driving ring circumferentially contacting the sealing ring is particularly applicable to sealing larger diameter concentric metallic members.

  3. Core disruptive accident margin seal

    DOEpatents

    Golden, Martin P.

    1979-01-01

    Apparatus for sealing the annulus defined within a substantially cylindrical rotatable riser assembly and plug combination of a nuclear reactor closure head. The apparatus comprises an inflatable sealing mechanism disposed in one portion of the riser assembly near the annulus such that upon inflation the sealing mechanism is radially actuated against the other portion of the riser assembly thereby sealing the annulus. The apparatus further comprises a connecting mechanism which places one end of the sealing mechanism in fluid communication with the reactor cover gas so that overpressurization of the reactor cover gas will increase the radial actuation of the sealing mechanism thus enhancing sealing of the annulus.

  4. Self-acting shaft seals

    NASA Technical Reports Server (NTRS)

    Ludwig, L. P.

    1978-01-01

    Self-acting seals are described in detail. The mathematical models for obtaining a seal force balance and the equilibrium operating film thickness are outlined. Particular attention is given to primary ring response (seal vibration) to rotating seat face runout. This response analysis reveals three different vibration models with secondary seal friction being an important parameter. Leakage flow inlet pressure drop and affects of axisymmetric sealing face deformations are discussed. Experimental data on self-acting face seals operating under simulated gas turbine conditions are given. Also a spiral groove seal design operated to 244 m/sec (800 ft/sec) is described.

  5. Seal system with integral detector

    DOEpatents

    Fiarman, S.

    1982-08-12

    A seal system is disclosed for materials where security is of the essence, such as nuclear materials. The seal is tamper-indicating, indicates changes in environmental conditions that evidence attempts to bypass the seal, is unique and cost effective. The seal system is comprised of a seal where an optical signal is transmitted through a loop, with a detector to read said signal, and one or more additional detectors designed to detect environmental changes, these detectors being operatively associated with the seal so that detection of a break in the optical signal or detection of environmental changes will cause an observable change in the seal.

  6. Radial pressure flange seal

    DOEpatents

    Batzer, T.H.; Call, W.R.

    1989-01-24

    This invention provides an all metal seal for vacuum or pressure vessels or systems. This invention does not use gaskets. The invention uses a flange which fits into a matching groove. Fluid pressure is applied in a chamber in the flange causing at least one of the flange walls to radially press against a side of the groove creating the seal between the flange wall and the groove side. 5 figs.

  7. Radial pressure flange seal

    DOEpatents

    Batzer, Thomas H.; Call, Wayne R.

    1989-01-01

    This invention provides an all metal seal for vacuum or pressure vessels or systems. This invention does not use gaskets. The invention uses a flange which fits into a matching groove. Fluid pressure is applied in a chamber in the flange causing at least one of the flange walls to radially press against a side of the groove creating the seal between the flange wall and the groove side.

  8. Titanium hermetic seals

    DOEpatents

    Brow, Richard K.; Watkins, Randall D.

    1995-07-04

    Titanium is prenitrided by being heated in a nitrogen environment under conditions which give rise to the formation of a titanium-nitride surface layer on the titanium. Titanium thus prenitrided may be used in electrical components which are hermetically sealed using silicate glasses and standard glass sealing techniques. According to the method of the invention, alkali volatilization and formation of deleterious interfacial silicide are inhibited.

  9. Titanium hermetic seals

    DOEpatents

    Brow, Richard K.; Watkins, Randall D.

    1995-01-01

    Titanium is prenitrided by being heated in a nitrogen environment under conditions which give rise to the formation of a titanium-nitride surface layer on the titanium. Titanium thus prenitrided may be used in electrical components which are hermetically sealed using silicate glasses and standard glass sealing techniques. According to the method of the invention, alkali volatilization and formation of deleterious interfacial silicide are inhibited.

  10. Double face sealing device

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce (Inventor)

    1991-01-01

    A double face sealing device is disclosed for mounting between two surfaces to provide an air-tight and fluid-tight seal between a closure member bearing one of the surfaces and a structure or housing bearing the other surface which extends around the opening or hatchway to be closed. The double face sealing device includes a plurality of sections or segments mounted to one of the surfaces, each having a main body portion, a pair of outwardly extending and diverging, cantilever, spring arms, and a pair of inwardly extending and diverging, cantilever, spring arms, an elastomeric cover on the distal, free ends of the outwardly extending and diverging spring arms, and an elastomeric cover on the distal, free, ends of the outwardly extending and diverging spring arms, and an elastomeric cover on the distal, free ends of the inwardly extending and diverging spring arms. The double face sealing device has application or use in all environments requiring a seal, but is particularly useful to seal openings or hatchways between compartments of spacecraft or aircraft.

  11. Nuclear instrumentation cable end seal

    DOEpatents

    Cannon, Collins P.; Brown, Donald P.

    1979-01-01

    An improved coaxial end seal for hermetically sealed nuclear instrumentation cable exhibiting an improved breakdown pulse noise characteristic under high voltage, high temperature conditions. A tubular insulator body has metallized interior and exterior surface portions which are braze sealed to a center conductor and an outer conductive sheath. The end surface of the insulator body which is directed toward the coaxial cable to which it is sealed has a recessed surface portion within which the braze seal material terminates.

  12. Pressure Actuated Leaf Seals for Improved Turbine Shaft Sealing

    NASA Technical Reports Server (NTRS)

    Grondahl, Clayton

    2006-01-01

    This presentation introduces a shaft seal in which leaf seal elements are constructed from slotted shim material formed and layered into a frusto-conical assembly. Limited elastic deflection of seal leaves with increasing system pressure close large startup clearance to a small, non-contacting, steady state running clearance. At shutdown seal elements resiliently retract as differential seal pressure diminishes. Large seal clearance during startup and shutdown provides a mechanism for rub avoidance. Minimum operating clearance improves performance and non-contacting operation promises long seal life. Design features of this seal, sample calculations at differential pressures up to 2400 psid and benefit comparison with brush and labyrinth seals is documented in paper, AIAA 2005 3985, presented at the Advanced Seal Technology session of the Joint Propulsion Conference in Tucson this past July. In this presentation use of bimetallic leaf material will be discussed. Frictional heating of bimetallic leaf seals during a seal rub can relieve the rub condition to some extent with a change in seal shape. Improved leaf seal rub tolerance is expected with bimetallic material.

  13. Serum chemistry and antibodies against pathogens in antarctic fur seals, Weddell seals, crabeater seals, and Ross seals.

    PubMed

    Tryland, Morten; Nymo, Ingebjørg H; Nielsen, Ole; Nordøy, Erling S; Kovacs, Kit M; Krafft, Bjørn A; Thoresen, Stein I; Åsbakk, Kjetil; Osterrieder, Klaus; Roth, Swaantje J; Lydersen, Christian; Godfroid, Jacques; Blix, Arnoldus S

    2012-07-01

    Information on health parameters, such as antibody prevalences and serum chemistry that can reveal exposure to pathogens, disease, and abnormal physiologic conditions, is scarce for Antarctic seal species. Serum samples from Antarctic fur seals (Arctocephalus gazella, n=88) from Bouvetøya (2000-2001 and 2001-2002), and from Weddell seals (Leptonychotes weddellii, n=20), Ross seals (Ommatophoca rossii, n=20), and crabeater seals (Lobodon carcinophagus, n=9) from the pack-ice off Queen Maud Land, Antarctica (2001) were analyzed for enzyme activity, and concentrations of protein, metabolites, minerals, and cortisol. Adult Antarctic fur seal males had elevated levels of total protein (range 64-99 g/l) compared to adult females and pups (range 52-79 g/l). Antarctic fur seals had higher enzyme activities of creatine kinase, lactate dehydrogenase, and amylase, compared to Weddell, Ross, and crabeater seals. Antibodies against Brucella spp. were detected in Weddell seals (37%), Ross seals (5%), and crabeater seals (11%), but not in Antarctic fur seals. Antibodies against phocine herpesvirus 1 were detected in all species examined (Antarctic fur seals, 58%; Weddell seals, 100%; Ross seals, 15%; and crabeater seals, 44%). No antibodies against Trichinella spp., Toxoplasma, or phocine distemper virus (PDV) were detected (Antarctic fur seals were not tested for PDV antibodies). Antarctic seals are challenged by reduced sea ice and increasing temperatures due to climate change, and increased anthropogenic activity can introduce new pathogens to these vulnerable ecosystems and represent a threat for these animals. Our data provide a baseline for future monitoring of health parameters of these Antarctic seal species, for tracking the impact of environmental, climatic, and anthropogenic changes in Antarctica over time. PMID:22740529

  14. Reactor coolant seal testing under station blackout conditions

    SciTech Connect

    Marsi, J.A.

    1988-01-01

    Failures of reactor coolant pump (RCP) seals that could result in a significant loss-of-coolant inventory are of current concern to the US Nuclear Regulatory Commission. Particular attention is being focused on seal behavior during station blackout conditions, when failure of on-site emergency diesel generators occurs simultaneously with loss of all off-site alternating current power. Under these conditions, both seal injection flow and component cooling water flow are lost, and the RCP seals are exposed to full reactor coolant temperature. Overheating of elastomeric components and flashing of coolant across the sealing faces can cause unacceptably high leakage rates, with potential catastrophic consequences. A test program has been conducted that subjects full-scale seal cartridges to typical pressurized water reactor (PWR) coolant system steady-state and transient operation conditions including associated dynamic shaft motions. A special test segment was developed to evaluate seal operation under station blackout conditions. The test program successfully mirrored the severity of an actual loss-of-seal cooling water event under station blackout conditions, and the Byron Jackson{reg sign} N-9000 seal cartridge maintained its integrity.

  15. A coupled mechanical/hydrologic model for WIPP shaft seals

    SciTech Connect

    Ehgartner, B.

    1991-06-01

    Effective sealing of the Waste Isolation Pilot Plant (WIPP) shafts will be required to isolate defense-generated transuranic wastes from the accessible environment. Shafts penetrate water-bearing hard rock formations before entering a massive creeping-salt formation (Salado) where the WIPP is located. Short and long-term seals are planned for the shafts. Short-term seals, a composite of concrete and bentonite, will primarily be located in the hard rock formations separating the water-bearing zones from the Salado Formation. These seals will limit water flow to the underlying long-term seals in the Salado. The long-term seals will consist of lengthly segments of initially unsaturated crushed salt. Creep closure of the shaft will consolidate unsaturated crushed salt, thereby reducing its permeability. However, water passing through the upper short-term seals and brine inherent to the salt host rock itself will eventually saturate the crushed salt and consolidation could be inhibited. Before saturating, portions of the crushed salt in the shafts are expected to consolidate to a permeability equivalent to the salt host rock, thereby effectively isolating the waste from the overlying water-bearing formations. A phenomenological model is developed for the coupled mechanical/hydrologic behavior of sealed WIPP shafts. The model couples creep closure of the shaft, crushed salt consolidation, and the associated reduction in permeability with Darcy's law for saturated fluid flow to predict the overall permeability of the shaft seal system with time. 17 refs., 6 figs., 1 tab.

  16. Winter Habitat Preference of Weddell Seals in the Ross Sea

    NASA Astrophysics Data System (ADS)

    Goetz, K. T.; Costa, D. P.; Robinson, P.; Burns, J. M.; Pearson, L.

    2010-12-01

    Weddell seals are important top predators in the Southern Ocean, yet very little data exist on their overwinter diving and foraging behavior when darkness and heavy ice cover prevail. To gain insight on both Weddell seal ecology and the oceanography of the Ross Sea during the winter, we outfitted 22 animals around Ross Island and up the Victorialand coast with Conductivity Temperature Depth - Satellite Relayed Data Logger (CTD-SRDL) tags. To date, over 75,000 dives and 4,000 CTD casts have been recorded. On average, Weddell seals dived to 210 m with a max dive depth of 969 m for nearly an hour in duration. While many seals spent a substantial amount of time in the area where they were tagged, several animals traveled over 1000 km from the tag deployment location: twice as far as shown in previous studies. Areas near Roosevelt and Coulman Islands appear to be important for Weddell seals as indicated by the increased diving per square kilometer. In fact, diving density, transit rate, and time spent in a given area reveal identical ‘hotspots’, possible foraging locations. While there appears to be some individual variation, Weddell seals prefer low slope (flat benthos) and water depths between 350 and 550 meters. Using the seal-generated temperature and conductivity casts, we also report the oceanographic conditions in these areas to gain a better understanding of Weddell seal habitat preferences and behavior in relation to oceanographic features. Obtaining information on how Weddell seals respond to their environment is necessary to predict how seal populations in highly dynamic systems are likely to respond to shifting environmental conditions associated with global climate change. Forage index for Weddell seals after correcting for tagging location

  17. Shaft seal assembly and method

    NASA Technical Reports Server (NTRS)

    Keba, John E. (Inventor)

    2007-01-01

    A pressure-actuated shaft seal assembly and associated method for controlling the flow of fluid adjacent a rotatable shaft are provided. The seal assembly includes one or more seal members that can be adjusted between open and closed positions, for example, according to the rotational speed of the shaft. For example, the seal member can be configured to be adjusted according to a radial pressure differential in a fluid that varies with the rotational speed of the shaft. In addition, in the closed position, each seal member can contact a rotatable member connected to the shaft to form a seal with the rotatable member and prevent fluid from flowing through the assembly. Thus, the seal can be closed at low speeds of operation and opened at high speeds of operation, thereby reducing the heat and wear in the seal assembly while maintaining a sufficient seal during all speeds of operation.

  18. Oil Saving Seal

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Driven under difficult field conditions, the Army Jeep shown went more than 22,000 miles without an oil change in a test conducted by the U.S. Army Mobility Equipment Research and Development Command. Key to this exceptionally long oil life was a set of piston ring seals made of a new synthetic rubber formula called RC-34; the seal pictured, photographed after its arduous Army trial, shows no signs of deterioration. The seal and the RC-34 material, which may soon be available for use in the family auto, were developed by Ramsey Corporation, St. Louis, Missouri, a division of TRW Automotive Worldwide. The oil in an automobile engine must be I replaced every few thousand miles not because it wears out but because it becomes contaminated. The contamination sources are gasoline and combustion gases which blow by the piston rings to mix with the oil, reducing the oil's ability to lubricate properly. Seeking to prolong oil life by eliminating "blowby," Ramsey Corporation looked for a better way to seal piston rings and used NASA technology as a departure point. The parent company TRW, under contract to NASA's Jet Propulsion Laboratory, had developed seals and bladders from a type of material called elastomers which where designed to withstand the environmental extremes of interplanetary flight. That effort formed a knowledge base for research which culminated in Ramsey's RC-34 elastomer.

  19. Taper-seal type metal sealing system and available applications

    NASA Astrophysics Data System (ADS)

    Kurokouchi, Satoshi; Okabe, Masayuki; Morita, Shinsaku

    2001-01-01

    A conventional disk (flat ring) gasket for ConFlat ® sealing system has been commonly applied to commercially available equipments for ultrahigh vacuum systems. However, its large redundant part which wastes the tightening force makes its handling and seal reliability problematic. We examine a taper-seal type gasket, which is newly designed to improve the inefficiency of ConFlat mechanism using conventional disk gaskets. It is remarked that the obtained seal area on a taper-seal type gasket is 1.6˜3.7 times larger than that of a conventional disk gasket. Our numencal results on stress distributions in a tightened gasket indicate that taper-seal gasket realizes highly stable seal pressure even under a lower tightening torque. High sealing reliability is thus achieved as expected which is mainly due to the wide seal area and stable seal pressure realized even for rather hard gasket material. Taper-seal type gasket also has some practical advantages. The most important of them may be that it enables to construct new edgeless metal sealing systems without a welded heavy flange. Here, edgeless sealing systems are composed of highly flexible incorporating viewports, bellows, feedthroughs, and blank-off covers, as well as any other conventional vacuum components.

  20. Brush seals for cryogenic applications

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P.

    1993-01-01

    Brush seals are compliant, contacting seals and have significantly lower leakage than labyrinth seals in gas turbine applications. Their characteristics of long life and low leakage make them candidates for use in rocket engine turbopumps. Two-inch diameter brush seals with a nominal 0.005 inch radial interference were tested in liquid nitrogen at shaft speeds up to 35,000 rpm and pressure drops up to 175 psid per seal. A labyrinth seal was also tested to provide a baseline. Performance, staging effects, and wear results are presented.

  1. Brush seals for cryogenic applications

    NASA Astrophysics Data System (ADS)

    Proctor, Margaret P.

    1993-11-01

    Brush seals are compliant, contacting seals and have significantly lower leakage than labyrinth seals in gas turbine applications. Their characteristics of long life and low leakage make them candidates for use in rocket engine turbopumps. Two-inch diameter brush seals with a nominal 0.005 inch radial interference were tested in liquid nitrogen at shaft speeds up to 35,000 rpm and pressure drops up to 175 psid per seal. A labyrinth seal was also tested to provide a baseline. Performance, staging effects, and wear results are presented.

  2. Seal system with integral detector

    DOEpatents

    Fiarman, Sidney

    1985-01-01

    There is disclosed a seal system for materials where security is of the essence, such as nuclear materials, which is tamper-indicating, which indicates changes in environmental conditions that evidence attempts to by-pass the seal, which is unique and cost effective, said seal system comprised of a seal where an optical signal is transmitted through a loop, with a detector to read said signal, and one or more additional detectors designed to detect environmental changes, these detectors being operatively associated with the seal so that detection of a break in the optical signal or detection of environmental changes will cause an observable change in the seal.

  3. Design guide for helicopter transmission seals

    NASA Technical Reports Server (NTRS)

    Hayden, T. S.; Keller, C. H., Jr.

    1974-01-01

    A detailed approach for the selection and design of seals for helicopter transmissions is presented. There are two major types of seals presently being used and they are lip type seals and mechanical type seals. Lip type seals can be divided in conventional lip seals and hydrodynamic lip seals. Conventional lip seals can be used for slow-speed, low-pressure, low-temperature sealing. Hydrodynamic lip seals although they are as pressure and temperature limited as conventional lip seals, can operate at a higher speed. Mechanical types seals are comprised of face seals and circumferential seals. Face seals are capable of high speed, high pressure, and high temperature. Circumferential seals can be used in high-speed and high-temperature applications, but will leak excessively at moderate pressures. The performance goals of transmission seals are a life that is at least equal to the scheduled overhaul interval of the gearbox component and a leakage rate of near zero.

  4. Morbilliviral dermatitis in seals.

    PubMed

    Lipscomb, T P; Mense, M G; Habecker, P L; Taubenberger, J K; Schoelkopf, R

    2001-11-01

    A juvenile female hooded seal (Cystophora cristata) and a juvenile male harp seal (Phoca groenlandica) stranded separately on the New Jersey (USA) coast and were taken to a marine mammal rehabilitation center. Both were lethargic and emaciated, had dermatitis, and died. Histologic skin lesions in the seals were similar and consisted of epidermal and follicular epithelial hyperplasia, hyperkeratosis, degeneration, and necrosis. The most distinctive finding was extensive syncytial zones bounded superficially by hyperkeratosis and deeply by hyperplastic basal cells. Eosinophilic intracytoplasmic inclusion bodies were present in epithelial cells. Morbilliviral antigen was demonstrated in the skin lesions by immunohistochemistry. Phocine distemper virus was detected in the skin by reverse transcription polymerase chain reaction and a phocine distemper virus-specific probe using the Southern blot technique. This is the first report of morbilliviral dermatitis in marine mammals. PMID:11732810

  5. REACTOR COOLANT TUBE SEAL

    DOEpatents

    Morris, W.J.

    1958-12-01

    A plle-flattenlng control element and a fluid seal therefore to permit movement of the element into a liquld contnining region of a neutronlc reactor are described. The device consists of flattened, thin-walled aluminum tubing contalnlng a uniform mixture of thermal neutron absorbing material, and a number of soft rubber closures for the process tubes, having silts capable of passing the flattened elements therethrough, but effectively sealing the process tubes against fluld leaknge by compression of the rubber. The flattened tubing is sufficiently flexible to enable it to conform to the configuratlon of the annular spacing surrounding the fuel elements ln the process tubes.

  6. Method of sealing

    DOEpatents

    Groh, Edward F.; Cassidy, Dale A.

    1978-01-01

    A thermocouple lead or other small diameter wire, cable or tube is passed through a thin material such as sheet metal and sealed thereinto by drawing complementary longitudinally angled, laterally rounded grooves terminating at their base ends in a common plane in both sides of the thin material with shearing occuring at the deep end faces thereof to form a rounded opening in the thin material substantially perpendicular to the plane of the thin material, passing a thermocouple lead or similar object through the opening so formed and sealing the opening with a sealant which simultaneously bonds the lead to the thin material.

  7. Corneal seal device

    NASA Technical Reports Server (NTRS)

    Baehr, E. F. (Inventor)

    1977-01-01

    A corneal seal device is provided which, when placed in an incision in the eye, permits the insertion of a surgical tool or instrument through the device into the eye. The device includes a seal chamber which opens into a tube which is adapted to be sutured to the eye and serves as an entry passage for a tool. A sealable aperture in the chamber permits passage of the tool through the chamber into the tube and hence into the eye. The chamber includes inlet ports adapted to be connected to a regulated source of irrigation fluid which provides a safe intraocular pressure.

  8. Emerging Sealing Technologies Development

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Under this Cooperative Agreement, the objective was to investigate several emerging sealing technologies of interest to the Mechanical Components Branch of National Aeronautics and Space Administration Glenn Research Center at Lewis Field (NASA GRC). The majority of the work conducted was to support the development of Solid Oxide Fuel Cells for application to aeronautic auxiliary power units, though technical investigations of interest to other groups and projects were also conducted. In general, accomplishments and results were periodically reported to the NASA Technical Monitor, the NASA GRC Seal Team staff, and NASA GRC project management. Several technical reports, journal articles, and presentations were given internally to NASA GRC and to the external public.

  9. Dye filled security seal

    DOEpatents

    Wilson, Dennis C. W.

    1982-04-27

    A security seal for providing an indication of unauthorized access to a sealed object includes an elongate member to be entwined in the object such that access is denied unless the member is removed. The elongate member has a hollow, pressurizable chamber extending throughout its length that is filled with a permanent dye under greater than atmospheric pressure. Attempts to cut the member and weld it together are revealed when dye flows through a rupture in the chamber wall and stains the outside surface of the member.

  10. Rotating Intershaft Brush Seal Project

    NASA Technical Reports Server (NTRS)

    Krawiecki, Stephen; Mehta, Jayesh; Holloway, Gary

    2006-01-01

    The pursuit of high Mach number flight presents several challenges to the airframe and engine design engineers. Most obvious is the resulting high temperatures encountered as the aircraft approaches Mach 3 and above. The encountered high temperatures and shaft speeds of engines require rethinking in the areas of material selections, component design and component operating life. In the area of sump compartment sealing, one of the most difficult sealing applications is the sealing of an engine s rear sump. Normally this sump will need some method of sealing between two rotating shafts. This sealing operation is done with an intershaft seal. The aft sump region also presents an additional design requirement for the intershaft seal. This region has to absorb the engine s thermal growth, which means that in the seal area, axial movement, on the order of 0.30 in., between the rotating shafts must be tolerated. A new concept or new technology of sealing an intershaft sump configuration is being developed. This concept, called a rotating intershaft brush seal has key attributes that will allow this seal to perform better, in the demanding environment of sealing an aft sump with two rotating shafts, when compared to today s sealing technology of labyrinth and carbon sea

  11. Structural Design and Sealing Performance Analysis of Biomimetic Sealing Ring

    PubMed Central

    Han, Chuanjun

    2015-01-01

    In order to reduce the failure probability of rubber sealing rings in reciprocating dynamic seal, a new structure of sealing ring based on bionics was designed. The biomimetic ring has three concave ridges and convex bulges on each side which are very similar to earthworms. Bulges were circularly designed and sealing performances of the biomimetic ring in both static seal and dynamic seal were simulated by FEM. In addition, effects of precompression, medium pressure, speed, friction coefficient, and material parameters on sealing performances were discussed. The results show that von Mises stress of the biomimetic sealing ring distributed symmetrically in no-pressure static sealing. The maximum von Mises stress appears on the second bulge of the inner side. High contact stress concentrates on left bulges. Von Mises stress distribution becomes uneven under medium pressure. Both von Mises stress and contact stress increase when precompression, medium pressure, and rubber hardness increase in static sealing. Biomimetic ring can avoid rolling and distortion in reciprocating dynamic seal, and its working life is much longer than O-ring and rectangular ring. The maximum von Mises stress and contact stress increase with the precompression, medium pressure, rubber hardness, and friction coefficient in reciprocating dynamic seal. PMID:27019582

  12. Direct seal papers for horizontal form-fill-seal machine.

    PubMed

    Merritt, John

    2002-01-01

    Direct-seal papers are designed for minimal fibre lift, where the sealing layer is incorporated into the bottom web. There are applications where they are the most appropriate economical alternative to traditional coated papers for horizontal form-fill-seal packaging. This article explores their benefits and limitations. PMID:11921779

  13. Structural Design and Sealing Performance Analysis of Biomimetic Sealing Ring.

    PubMed

    Han, Chuanjun; Zhang, Han; Zhang, Jie

    2015-01-01

    In order to reduce the failure probability of rubber sealing rings in reciprocating dynamic seal, a new structure of sealing ring based on bionics was designed. The biomimetic ring has three concave ridges and convex bulges on each side which are very similar to earthworms. Bulges were circularly designed and sealing performances of the biomimetic ring in both static seal and dynamic seal were simulated by FEM. In addition, effects of precompression, medium pressure, speed, friction coefficient, and material parameters on sealing performances were discussed. The results show that von Mises stress of the biomimetic sealing ring distributed symmetrically in no-pressure static sealing. The maximum von Mises stress appears on the second bulge of the inner side. High contact stress concentrates on left bulges. Von Mises stress distribution becomes uneven under medium pressure. Both von Mises stress and contact stress increase when precompression, medium pressure, and rubber hardness increase in static sealing. Biomimetic ring can avoid rolling and distortion in reciprocating dynamic seal, and its working life is much longer than O-ring and rectangular ring. The maximum von Mises stress and contact stress increase with the precompression, medium pressure, rubber hardness, and friction coefficient in reciprocating dynamic seal. PMID:27019582

  14. Analysis Of Stepped Labyrinth Seals

    NASA Technical Reports Server (NTRS)

    Scharrer, Joseph K.

    1990-01-01

    Report presents analysis of compressible flow in stepped labyrinth gas seal in turbomachine. Part of continuing effort to understand and suppress self-excited vibrations caused by stepped labyrinth seals. Rotordynamic coefficients derived for compressible flow.

  15. Static seal for turbine engine

    SciTech Connect

    Salazar, Santiago; Gisch, Andrew

    2014-04-01

    A seal structure for a gas turbine engine, the seal structure including first and second components located adjacent to each other and forming a barrier between high and low pressure zones. A seal cavity is defined in the first and second components, the seal cavity extending to either side of an elongated gap extending generally in a first direction between the first and second components. A seal member is positioned within the seal cavity and spans across the elongated gap. The seal member includes first and second side edges extending into each of the components in a second direction transverse to the first direction, and opposing longitudinal edges extending between the side edges generally parallel to the first direction. The side edges include a groove formed therein for effecting a reduction of gas flow around the seal member at the side edges.

  16. Feather seal slot for vanes

    SciTech Connect

    Del Mastro, B. P.; Eckart, F.

    1985-10-22

    The slots for accommodating feather seals in the turbine vanes of a gas turbine engine has the end thereof sealed off by use of weld wire inserted into the slot and simultaneously welded and cut to the required length.

  17. Seal For Precooling A Turbopump

    NASA Technical Reports Server (NTRS)

    Owen, Samuel S.; Mulready, R.C.

    1988-01-01

    Diaphragm reduces misalignment. Rotary seal retains precooling fluid in pump section of cryogenic turbopump, preventing fluid from entering turbine section. Precooling fluid held in pump section of turbopump by knife-edge labyrinth seal on diaphragm.

  18. Multiple-Pulse Sounds and Seals: Results of a Harbor Seal (Phoca vitulina) Telemetry Study During Wind Farm Construction.

    PubMed

    Hastie, Gordon D; Russell, Debbie J F; McConnell, Bernie; Thompson, Dave; Janik, Vincent M

    2016-01-01

    Offshore construction and survey techniques can produce pulsed sounds with a high sound pressure level. In coastal waters, the areas in which they are produced are often also used by seals, potentially resulting in auditory damage or behavioral avoidance. Here, we describe a study on harbor seals during a wind farm installation off southeast England. The study used GPS/global system for mobile communication tags on 23 harbor seals that provided distribution and activity data; the closest range of individual seals to piling varied from 6.65 to 46.1 km. Furthermore, the maximum predicted received levels (RLs) at individual seals varied between 146.9 and 169.4 dB re 1 μPa peak to peak. PMID:26610987

  19. High temperature seals for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Parihar, Shailendra S.

    Solid Oxide Fuel cells (SOFCs) represent a clean and efficient alternative to existing methods of energy production. But, they need hermetic seals to prevent fuel-oxidant mixing within the stack. Glasses are attractive options for fabrication of these high temperature seals but suffer from their inherent brittleness and tend to crack during thermal cycling. In this study, an innovative concept of self-healing glass seals is developed to solve the problem of cracking of glasses in a SOFC seal. Rationale behind this concept is that a glass of suitable viscosity characteristics can flow and heal cracks at SOFC operating temperatures and thus can provide seals which can self-repair. A novel method, based on in-situ video imaging of cracks on the glass surface during high temperature treatment is developed and used to select and evaluate the suitability of different glasses for making self-healing seals. Promising glasses are studied experimentally to determine kinetics of healing of Vickers indented cracks at various temperatures. In addition, the effect of crystallization of glass on its healing kinetics is studied. A model is developed for crack healing behavior and is used to validate the experimental data. Studies on Cracks healing and crystallization of glasses showed that glasses with no crystallization tendency show fast crack healing response, whereas glasses which crystallize display sluggish healing. A glass displaying fast healing kinetics and good stability against crystallization is used to fabricate self healing glass seals for SOFCs. Seals fabricated using this glass not only remained hermetic but also maintained their self i healing ability for as long as 3000 hours at 800°C and 300 thermal cycles between room temperature and 800°C. These results clearly indicated that self-healing glasses are promising candidates for SOFC seals. Key words. Solid Oxide Fuel Cells, Glass Seals, Self-Healing Glasses, Seal Leak Testing.

  20. Finger Seal: A Novel Approach to Air to Air Sealing

    NASA Technical Reports Server (NTRS)

    Arora, Gul; Steinetz, Bruce; Proctor, Margaret

    2006-01-01

    The gas turbine industry used a variety of sealing mechanisms to contain and direct secondary flows into and around components for cooling, and to limit leakage into and from bearing and disk cavities. The function of these seals is very important to the component efficiencies and attendant engine performance. Most of these seals are labyrinth seals, which are high-leakage seals that are costly to manufacture. In recent years, brush seals have been introduced which have demonstrated significantly reduced leakage, although they are still expensive and have exhibited wear and hysteresis difficulties. A new innovative concept called finger seal, patented by AlliedSignal, has demonstrated leakage similar to brush seals and is cheaper. The finger seal is comprised of a stack of precision photo-etched sheet metal elements, which allows intricate features to be made at very low cost and with the potential to resist wear and provide the compliance necessary to accomodate rotor excursions. Initial testing in the high-speed/high-temperature seal test facility, at the NASA Lewis Research Center, has corroborated the finger seal performance. The testing also revealed hysteresis problems with the current design. A NASA funded research project is in progress to correct the functional deficiencies of the finger seal and to refine its features to provide sufficient seal life for commercial transport engines and other long-life applications. This research will benefit the aeronautical gas turbine industry as a whole in terms of fuel consumption, operational characteristics, and cost. The first phase of this research to reduce finger seal hysteresis has been in progress for the last one year. This paper presents the results of this research to date. In future the research program will address seal performance, manufacturing, cost and life issues. The research program is expected to be completed by December 1998.

  1. Turbine engine interstage seal

    SciTech Connect

    Clevenger, L.L.

    1993-08-10

    A seal structure is described for a turbine engine, the turbine engine including a housing surrounding a centrifugal compressor having a rotor, and a radial inflow turbine including a turbine rotor, the compressor rotor and the turbine rotor being disposed in back-to-back relation, the turbine rotor being drivingly connected with the compressor rotor and axially spaced therefrom to define an annular gap there between, the gap radially bounded at its outer periphery by the housing and at its inner periphery by an annular surface intermediate the compressor rotor and the turbine rotor an annular sealing member disposed in the gap to control air flow from the compressor toward the turbine; the annular sealing member the first axial direction, and a third annular wall portion joining with the second annular wall portion and extending inward therefrom towards the surface intermediate the compressor rotor and the turbine rotor, and biasing means cooperating with the housing for urging the seal structure toward the turbine rotor.

  2. Damping seal for turbomachinery

    NASA Technical Reports Server (NTRS)

    Vonpragenau, G. L. (Inventor)

    1985-01-01

    A damping seal between a high speed rotor member and stator member that separates pressurized fluid compartments is described. It is characterized by the rotor member having a smooth outer surface and the stator member having its bore surface roughened by a plurality of pockets or depressions.

  3. Ceramic to metal seal

    DOEpatents

    Snow, Gary S.; Wilcox, Paul D.

    1976-01-01

    Providing a high strength, hermetic ceramic to metal seal by essentially heating a wire-like metal gasket and a ceramic member, which have been chemically cleaned, while simultaneously deforming from about 50 to 95 percent the metal gasket against the ceramic member at a temperature of about 30 to 75 percent of the melting temperature of the metal gasket.

  4. "The Seventh Seal."

    ERIC Educational Resources Information Center

    Palmer, Peter M.

    1969-01-01

    The significance of Bergman's "Seventh Seal" lies not in the speeches nor in the actions of the central characters but rather in the film's form, its totality created by the emotive elements of imagery and sound together with the intellectual elements of actions and words. The scene-units are related to a central motif (the opening of the seventh…

  5. Keepers of the Seals.

    ERIC Educational Resources Information Center

    Momatiuk, Yva; Eastcott, John

    1998-01-01

    The Pribilof Islands Stewardship Program aims to preserve the rich species diversity of the islands and recover the sense of connectedness that once linked local Aleuts and their environment. The summer program draws on both science and traditional knowledge, offering Aleut youth the chance to assist scientists, protect the seals, and participate…

  6. Sealing an ultracapacitor

    DOEpatents

    Irwin, Patricia Chapman; Feist, Thomas Paul

    2001-10-16

    An ultracapacitor comprises at least one cell comprising two solid, nonporous current collectors, two porous electrodes separating the current collectors, a porous separator between the electrodes and an electrolyte occupying pores in the electrodes and separator. The cell is sealed with a reclosable hermetic closure.

  7. GOLD PRESSURE VESSEL SEAL

    DOEpatents

    Smith, A.E.

    1963-11-26

    An improved seal between the piston and die member of a piston-cylinder type pressure vessel is presented. A layer of gold, of sufficient thickness to provide an interference fit between the piston and die member, is plated on the contacting surface of at least one of the members. (AEC)

  8. Piston rod seal

    DOEpatents

    Lindskoug, Stefan

    1984-01-01

    In a piston rod seal of the type comprising a gland through which the piston rod is passed the piston is provided with a sleeve surrounding the piston rod and extending axially so as to axially partly overlap the gland when the piston is in its bottom dead center position.

  9. Ultrasonic dip seal maintenance system

    DOEpatents

    Poindexter, Allan M.; Ricks, Herbert E.

    1978-01-01

    A system for removing impurities from the surfaces of liquid dip seals and or wetting the metal surfaces of liquid dip seals in nuclear components. The system comprises an ultrasonic transducer that transmits ultrasonic vibrations along an ultrasonic probe to the metal and liquid surfaces of the dip seal thereby loosening and removing those impurities.

  10. Seal for sodium sulfur battery

    DOEpatents

    Topouzian, Armenag; Minck, Robert W.; Williams, William J.

    1980-01-01

    This invention is directed to a seal for a sodium sulfur battery in which the sealing is accomplished by a radial compression seal made on a ceramic component of the battery which separates an anode compartment from a cathode compartment of the battery.